cassava breeding, agronomy and farmer participatory

Cassava Breeding, Agronomy and Farmer

Participatory Research in Asia

Proceedings of the Fifth Regional Workshop

held in Danzhou, Hainan, China, Nov 3-8, 1996

CATAS

CIAT

The Nippon Foundation

The International Center for Tropical Agriculture (CIAT, its Spanish

acronym) is dedicated to the alleviation of hunger and poverty in developing

countries of the tropics. CIAT applies science to agriculture to increase food

production while sustaining the natural resource base.

CIAT is one of 16 international agricultural.research centers sponsored

by the Consultative Group on International Agricultural Research (CGIAR).

The Center.s core budget is financed by 27 donor countries,

international and regional development organizations, and private foundations.

In 1996, the donor countries include Australia, Belgium, Brazil, Canada, China,

Colombia, Denmark, France, Germany, Japan, Mexico, the Netherlands,

Norway, Spain, Sweden, Switzerland, the United Kingdom, and the United

States of America. Donor organizations include the European Union (EU), the

Ford Foundation, the Inter-American Development Bank (IDB), the International

Development Research Centre (IDRC), the International Fund for Agricultural

Development (IFAD), the Nippon Foundation, the Rockefeller Foundation, the

United Nations Development Programme (UNDP), and the World Bank.

Information and conclusions reported in this document do not

necessarily reflect the position of any donor agency.

Cassava Breeding, Agronomy and Farmer

Participatory Research in Asia

Proceedings of the Fifth Regional Workshop

held at CATAS, Danzhou, Hainan, China, Not 3-8, 1996.

Technical Editor: R.H. Howeler

Organized by Centro Internacional de Agricultura Tropical (CIAT) and the

Chinese Academy of Tropical Agricultural Sciences (CATAS)

With financial support from

- Nippon Foundation, Tokyo, Japan

- Government of Japan

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Cover photo:

R.H. Howeler

Harvest of Farmer Participatory Research (FPR) trials on erosion control in Bac Thai

province of Vietnam.

Centro International de Agricultura Tropical (CIAT)

Apartado Aereo 67-13, Cali, Colombia

CIAT Regional Cassava Programfor Asia

Field Crops Research Institute

Department ofAgriculture

Chatuchak, Bangkok 10900

Thailand

April, 1998

Print Order: 400 Copies

Reference: Centro International de Agricultura Tropical (CIAT). 1998. Cassava

Breeding, Agronomy and Farmer Participatory Research in Asia. Proc.

Fifth Regional Workshop held in Danzhou, Hainan China. Nov 3-8,

1996.

I. Cassava Asia-Breeding-Agronomy-Farmer Participatory Research

II. Howeler, R.H.

III. Centro Internacional de Agricultura Tropical

PREFACE

The Centro Internacional de Agricultura Tropical (CIAT), with headquarters in

Colombia, has as its mission "to contribute to the alleviation of hunger and poverty in

tropical developing countries by applying science to the generation of technology, leading

to lasting increases in agricultural outputs while preserving the natural resource base".

The ultimate goal is to reduce hunger and poverty through the development of sustainable

agriculture, mainly by integrating programs on genetic improvement with those on natural

resources management. The two programs are intimately linked, as sustainable land use

and resource management will contribute to conserving biodiversity, which is a vital

resource for crop improvement. Conversely, more productive germplasm will enable

farmers to increase their yield and raise their income, giving them more resources and

incentives to conserve the productivity of their soil and prevent erosion.

CIAT can not achieve this goal alone, but only in partnership with national and

international research institutions. Moreover, in order to enhance the adaption of new

technologies, CIAT also collaborates closely with extension organizations and strongly

encourages farmer participation in technology development and dissemination.

Within the Consultative Group for International Agricultural Research (CGIAR).

CIAT has the world mandate for research on cassava production and utilization, while

the International Institute for Tropical Agriculture (IITA), located in Nigeria, has

responsibility for cassava research in Africa. In order to facilitate communication with

national cassava research programs in Asia, CIAT established a Regional Cassava Office

in Bangkok, Thailand, in 1983. Through this Regional Office, a network of cassava

researchers in national research institutes and universities in Asia was established, with

the objective of enhancing communication between researchers, both within and among

countries, in order to increase the efficiency of cassava research with the goal of

improving the productivity and utilization of the crop. This will ultimately contribute to

increased incomes and improvements in the standard of living of cassava producers,

processors and consumers.

To further enhance communication among cassava researchers in Asia, the CIAT

Regional Office has organized Regional Cassava Workshops every three years. These

workshops bring together many cassava researchers from different countries in Asia, who

present the latest progress in their research, mainly in the areas of cassava breeding and

soil/crop management or agronomy. The first workshop was held in Bangkok in 1984

to review the general situation of cassava in Asia, to identify the major constraints and

set research priorities. The second workshop was held in Rayong, Thailand in 1987 to

review the first year's results in cassava crop improvement and to summarize all

agronomic research that had been conducted prior to that date by national programs.

From this review it was concluded that future agronomic research in Asia should

emphasize mainly the maintenance and improvement of soil fertility and the effective

control of soil erosion. The third workshop was held in Malang, Indonesia in 1990.

This workshop not only reviewed the recent progress in cassava breeding and agronomy,

but also research on cassava utilization, both for human and animal consumption as well

as for industrial usage. The fourth workshop was held in Trivandrum, Kerala, India in

1993 to review the latest progress in breeding and agronomy, as well as to discuss more

effective ways to transfer the new technologies to farmers in order to achieve adoption

and impact. In this workshop extension specialists from several countries were invited

to share their experiences and to join the researchers in the cassava network. This will

further enhance the adoption of many new cassava varieties that have recently been

released, as well as that of new and more sustainable production practices. The

workshop was also an opportunity to discuss a proposal, submitted for funding to the

Nippon Foundation in Japan, to develop a Farmer Participatory Research (FPR)

methodology, mainly to enhance the adoption of more sustainable management practices

in cassava-based cropping systems in Asia. The Nippon foundation approved the project

in late 1993 for a five-year period. It has funded all activities in the area of cassava

soil/crop management research, farmer participatory research and training in FPR

methodologies.

The fifth workshop was held at CATAS in Danzhou, Hainan, China in November

1996. Besides reviewing further progress in cassava varietal improvement and

disemmination as well as agronomy research, it provided an opportunity to present and

discuss the first results of the FPR projects conducted in several pilot sites in various

countries in Asia. Based on these experiences future activities in the project were

discussed. The papers presented in this 5th Regional Workshop are published in this

Proceedings.

During the fifth Regional Workshop in China the Advisory Committee for the

Asian Cassava Research Network met to discuss research priorities, the future outlook

for cassava research in Asia, and to decide on the theme, location and time for the Sixth

Regional Workshop. During this meeting the following members were elected:

Pham Van Bien IAS, Vietnam: Chairman

Kazuo Kawano CIAT, Thailand: Secretary

Zheng Xueqin CATAS, China

G.T. Kurup CTCRI, India

Soemarjo Poespodarsono Brawijaya Univ, Indonesia

Tan Swee Lian MARDI, Malaysia

Fernando Evangelio PRCRTC, Philippines

Cham Tiraporn DOA, Thailand

Reinhardt Howeler CIAT, Thailand

During the meeting it was decided to organize the sixth workshop in Ho Chi Minh city,

Vietnam at the end of 1999.

CIAT wants to take this opportunity to express its gratitude to the Nippon

Foundation and the Government of Japan for their financial support, not only for funding

the collaborative research and extension activities reported here, but also the organization

of the fifth Workshop in China. Without their financial support the Asian Cassava

Research Network would not be sustainable.

We also like to thank all the members of the organizing committee, mainly from

CATAS, for their hard work and dedication in organizing this event. In spite of

unusually wet weather, they managed to organize an interesting field day to Kongba

village in Baisha county. All workshop participants also much appreciated the excellent

facilities and organization of the workshop, and especially, the delicious Chinese food.

Many thanks to all for their hard work.

R.H. Howeler

CIAT, Bangkok

April 1998

CONTENTS

Page

Preface 1

Trends, Constraints and Opportunities of the Asian

Cassava Sector: An Assessment 3

Guy Henry and Clair Hershey

Progress in Cassava Breeding at the Chinese Academy of

Tropical and Agricultural Sciences (CATAS) 21

Lin Xiong, Li Kaimian, Zhang Weite and Huang Jie

Cassava Varietal Improvement and Dissemination in Guangxi 34

Tian Yinong and Lee Jun

Breeding and Varietal Improvement in Thailand 48

Jarungsit Limsila, Atchara Limsila, Watana Watananonta

and Kazuo Kawano

Varietal Improvement and Dissemination by Kasetsart University,

the Thai Tapioca Development Institute, and the Dept. of

Agricultural Extension 55

Chareinsuk Rojanaridpiched, Somporn Phongvutipraphan,

Piyawuth Poolsanguan, Kaival Klakhaeng, Vichan Vichukit

and Ed Sarobol

Cassava Varietal Improvement in Vietnam 69

Tran Ngoc Ngoan, Ngoc Quyen, Trinh Phuong Loan

and Kazuo Kawano

Cassava Varietal Dissemination in Vietnam 82

Hoang Kim, Tran Ngoc Quyen, Pham Van Bien and Kazuo Kawano

Breeding and Varietal Improvement of Cassava in India 101

S.G Nair, P.G. Rajendran, S.K. Naskar, M.T. Sreekumari,

M. Unnikrishnan and M.N. Sheela

Cassava Research Program at Tamil Nadu Agricultural University

(TNAU) in India 1 1 1

S. Thamburaj

Recent Progress in Cassava Varietal Improvement in the Philippines 131

Algerico M. Mariscal and Reynaldo V. Bergantin

Recent Progress in Cassava Varietal Improvement in Indonesia 149

Soemarjo Poespodarsono

Cassava Varietal Improvement Program at Umas Jaya Farm and its

Contribution to Small Farmer Communities in Sumatra, Indonesia 156

Palupi Puspitorini, Usman Kartawijaya and Kazuo Kawano

Socio-Economic Contribution of Cassava Varietal Improvement

to the Small Farmer Communities in Asia 170

Kazuo Kawano

Cassava Agronomy Research in China 191

Zhang Weite, Lin Xiong, Li Kaimian, Huang Jie,

Tian Yinong, Lee Jun and Fu Quohui

Recent Progress in Cassava Agronomy Research in Thailand 211

A. Tongglum, V. Pornpromprathan, K. Paisarncharoen,

C. Wongviwatchai, C. Sittibusaya, S. Jantawat,

T. Nual-on and R.H. Howeler

Recent Progress in Cassava Agronomy Research in Vietnam 235

Nguyen Huu Hy, Pham Van Bien, Nguyen The Dang

and Thai Phien

Cassava Soils and Nutrient Management in South Vietnam 257

Cong Doan Sat and Pol Deturck

Nutrient Management for Cassava-Based Cropping Systems

in Northern Vietnam 268

Thai Phien and Nguyen Cong Vinh

Progress in Agronomy Research in India 280

C.R. Mohankumar, V.P. Potty, C.S. Ravindran,

S. Kabeerathumma and C.R. Sudharmai Devi

Recent Progress in Cassava Agronomy Research in Indonesia 307

J. Wargiono, Kushartoyo, Suyamto H. and B.. Guritno

Recent Progress in Cassava Agronomy Research in the Philippines 331

Fernando A. Evangelio and Julieta C. Ladera

Varietal Improvement and Agronomy Research in Malaysia 340

Tan Swee Lian

Cassava Agronomy Research in Asia - An Overview 1993-1996 355

Reinhardt H. Howeler

Farmer Participatory Adaptation and Adoption of Contour 376

Hedgerows for Soil Conservation

Sam Fujisaka

Farmer Participatory Research in Cassava Soil Management

and Varietal Dissemination in China 389

Zhang Weite, Lin Xiong, Li Kaimian and Huang Jie

Farmer Participatory Research in Soil Management and

Varietal Selection in Thailand 412

V. Vongkasem, K. Klakhaeng, S. Hemvijit, A. Tongglum,

S. Katong and D. Suparhan

Farmer Participatory Research in Cassava Technology Transfer

in India 438

S. Ramanathan and M. Anantharaman

Farmer Participatory Research in Cassava Soil Management

and Varietal Dissemination in Vietnam 454

Nguyen The Dang, Tran Ngoc Ngoan, Le Sy Loi,

Dinh Ngoc Lan and Thai Phien

Farmer Participatory Research in Soil Management in Indonesia 471

W.H. Utomo, Suyamto, H. Santoso and A. Sinaga

Farmers' Participation in Cassava Technology Transfer in

the Philippines 482

Editha A. Gundaya and Fernando A. Evangelio

Farmer Participatory Research for Cassava Technology Transfer

in Asia - Constraints and Opportunities 497

Reinhardt H. Howeler and Guy Henry

Cassava Biotechnology Network 515

Ann Marie Thro

Workshop Participants 525

Appendix. Results of Soil Analyses in Asia 1994-1997 530

Reinhardt H. Howeler

TRENDS, CONSTRAINTS AND OPPORTUNITIES OF THE ASIAN

CASSAVA SECTOR: AN ASSESSMENT1

Guy Henry2 and Clair Hershey3

ABSTRACT

This paper attempts to utilize past cassava production, utilization and market trends,

integrated with regional macro-economic developments, together with a general summary of

current cassava R&D advances, to analyze the principal cassava sector constraints and future

opportunities, both at the country and regional level.

The first section shows where the major cassava production and utilization areas are and

secondly assesses cassava area, yield and production trends from 1980-95 by region and specific

countries (cases), explaining past trends due to a variety of factors, including climatological,

biological, technological (R&D), political and macro-economic aspects.

The second section concentrates on the dynamics of cassava processing, products and

markets, analyzing the major cassava product groups, i.e. cassava for fresh direct consumption,

flours, dried cassava chips and pellets for animal feeds, and cassava starches. Evidence will be

presented to show the significant increases of starch production versus relative declines in pellets.

Macro-policy changes, expanded market demand, technology advances and relative price changes

are some of the major factors explaining these recent developments.

The third section of the paper assesses regional, market (and country) cassava sector

constraints which are stratified into four areas: (a) biological/technical aspects, (b) socio-economic

aspects, (c) institutional aspects, and (d) political aspects. For some of the aspects quantitative

evidence is presented; other aspects are more qualitatively assessed. After this, the most significant

future opportunities are analyzed. These are grouped into three areas: (a) technological, (b)

market, and (c) institutional/political.

The paper ends with the major conclusions and makes several recommendations.

CASSAVA PRODUCTION AND SYSTEMS TRENDS

The Asian continent currently produces about 46 million metric tons (t) of

cassava on 3.5 million hectares (1996). As such, it occupies second place in terms of

global cassava production, and first place in yield (13-14 t/ha). Two-thirds of total

production originates in Thailand and Indonesia alone. Seven countries account for 99%

of the region's production: Thailand, Indonesia, India, China, Vietnam, the Philippines

and Malaysia (Table 1). About 40% of cassava is used for direct human consumption,

especially in processed form. Most of the remainder is destined for animal feed or

processed for starch (FAOSTAT, 1997).

1 This document draws significantly on papers treating the same subject by Henry and Gottret

(1996) and Hershey et al. (1997).

2 Economist, CIRAD-PROAMYL, Montpellier, France; formerly Economist, Cassava

Program, CIAT, Cali, Colombia.

3 Consultant, Manheim, PA, USA; formerly Plant Breeder, Cassava Program, CIAT, Cali,

Colombia.

4

Table 1. Cassava area, yield and production in Asia in 1996.

Area Yield Production

(ha) (t/ha) (t)

Brunei 130 11.5 1,500

Cambodia 12,500 7.2 90,000

China 230,080 15.2 3,501,070

India 244,000 24.5 5,979,000

Indonesia 1,300,000 13.1 17,002,500

Laos 5,000 13.7 68,500

Malaysia 39,000 10.3 400,000

Maldives 8 2.5 20

Myanmar 7,300 9.3 68,000

Philippines 215,000 8.8 1,900,000

Singapore 1 10.0 10

Sri Lanka 32,000 9.1 290,000

Thailand 1,265,100 14.3 18,083,600

Vietnam 275,600 7.5 2,067,300

ASIA 3,625,719 13.6 49,451,500

Source: FAOSTAT, 1998

During the past decade, Asian cassava production experienced a growth rate of

0.30% per year. While cassava area experienced a decrease (-0.20%), yields increased

at an annual rate of 0.50%. From the 1980s to the present, the main influences on

cassava production and commerce were rapid growth in many Asian economies with

accompanying changes in food consumption patterns; increased demand from industry for

raw products such as starch; and increasing implementation of trade policies that reduced

cassava's preferential treatment in European markets. Except for a few products such as

krupuk in Indonesia, cassava generally enters markets where other calorie or industrial

starch sources may readily be substituted. Future growth, therefore, is largely linked to

cost competitiveness, or markets that require specific characteristics that only cassava

provides.

Thailand, is a cassava processed-product export-led country. Nearly all cassava

is grown on small farms of one to five hectares. Chipping and drying is done in nearby

commercial drying floors, while processing for starch is generally done in large factories.

The pellet export industry is heavily dependent on the middle-men who are usually

owners of trucks or drying floors, who consolidate production from these small farms

into processing and marketing channels. The various events that have led Thailand's

cassava industrialization development are well described by Titapiwatanakun (1996),

Henry and Gottret (1996), and Hershey et al. (1997). During the last decade, Thailand

has experienced a major diversification of its cassava product and market mix. While up

to the early 80's pellets represented 88% of cassava exports (almost entirely to the EU),

the pellet share by 1992 was down to 72% and continues to decrease, in favor of starch.

Furthermore, Thai starch factories are increasingly producing modified starches rather

than lower valued native starch. Total production peaked at 24 million tons in 1989 and

decreased to 18 million tons in 1996 (Figure 1).

For many years a single variety, Rayong 1, occupied almost 100% of the

country's area. This began changing in the mid-1980s as new hybrids gained popularity

due to market premium assigned to higher starch content. By 1996, new hybrids from

the cassava programs of the Dept. of Agriculture and of Kasetsart University extended

over about one-fourth of the total area. Private industry (mainly starch factories) and

national extension services play an important role in promotion and distribution of new

technology. Mechanized land preparation, fertilizer application, and mechanical or

chemical weed control are now common.

Despite the adoption of new varieties, Thai cassava yields show only a 0.12%

annual increase during the last decade (Henry and Gottret, 1996). This low figure is due

to a large extent to a shift of cassava production to more marginal areas, and because of

reduced fertilization as a consequence of depressed starch and pellet market prices.

Reduced fertilization on soils that have been monocropped for many years will show

adverse effects on yield, nothwithstanding improved varieties.

In Indonesia, the relatively stable area of planting across years is a function of

market diversity and comparative advantage in upland environments not suited for rice.

The multi-use characteristics are fully exploited and provide a range of market options

to stabilize prices. The traditional products in the internal markets are gaplek (dried

cassava chunks used in a variety of local dishes), and krupuk, a crispy snack wafer made

from cassava starch.

Production systems in Indonesia are in general more complex than elsewhere in

Asia. Intercropping is common, especially where there are not severe soil and water

constraints. Common intercrops are upland rice, maize and various legumes. On the outer

islands rainfall is usually less limiting, but poor soils are sometimes a constraint on the

ability to intercrop cereals and legumes. On Java, farms are small and intensively

managed, with few purchased inputs. The starch industry in Sumatra is based on large,

vertically integrated plantations where moderate input levels are applied, and new high-

yielding varieties planted. These industries have joined with the national program in

supporting production research, which has benefitted surrounding small independent

farmers as well as the plantations. The effects are becoming clear when analyzing

production trends. Over the last decade, production grew with a healthy annual 1 .2-1 .4%

(Figure 1), this growth being attributed to both increases in area (1.0%) and yield

(0.36%) (Henry and Gottret, 1996). Nonetheless, large areas of Indonesia have suffered

severe droughts during the past five years, and this is again the case in the 1997/98

season. Although this will much less effect cassava (relative to rice, etc.), production for

1998 is estimated to be down from earlier years (FAO, 1997).

Cassava cultivation in India is concentrated in the southern states of Kerala and

Tamil Nadu. The country is distinguished by the world's highest average cassava yields,

about 24 t/ha. These high yields are accomplished by intensive cultivation, and, in Tamil

Nadu, by irrigation. In Kerala, much of the production is consumed as boiled roots, one

of the few regions in Asia where this is common. Cooking quality is one of the principal

criteria farmers use in selecting varieties for cultivation. In Tamil Nadu nearly all of the

production is for starch and sago. Markets for fresh consumption have been slumped

during several years, drawing attention to the need for product and/or market

diversification. This trend has affected the planted area to cassava, which shows an

annual decline of more than 2%. Hence, less area, but with increasing productivity.

China produces cassava in the southern provinces of Guangxi, Guangdong, and

Hainan (and more recently in Yunnan). Most is planted with few production inputs on

hillsides surrounding rice paddies. Historically cassava was a famine reserve crop,

planted in marginal areas with high risk of crop failure. Production data from China are

not very reliable, but according to FAO, area peaked at 245,000 ha in 1983. Although

a minor crop in China as a whole, it is increasingly looked upon as an efficient producer

of raw material for starch and on-farm pig feeding. Nonetheless, its area is under severe

pressure from competing higher-value crops (fruit trees) and alternative land use.

Like Indonesia, the Philippines is a multi-island economy, but differs in that

population is spread more uniformly across different islands. Cassava fits well within an

agricultural policy that emphasizes self sufficiency in basic foods (except wheat), import

substitution, and development of the small farm sector. Cassava is produced throughout

the Philippines, but is more concentrated on the southern islands, especially the Visayas

region and Mindanao. Most production is on small farms, although there are some large

plantations supplying starch factories. Input use is low in comparison to other countries,

and this is reflected in some of the lowest yields in Asia. Nonetheless, yields in the past

ten years have climbed steadily from about 7 to about 9 t/ha, suggesting adoption of

improved varieties and cultural practices. Cassava area has increased steadily, from about

200,000 ha in 1984 to 215,000 ha in 1996.

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In Vietnam, the area planted to cassava peaked in 1979 at 460,000 ha, but then

declined to nearly half that level because of lack of markets and competition from other

crops. It occupies the poor soils of mountainous and hilly areas, mainly in monoculture

systems. Since many of these soils are highly erodible, their recuperation and

conservation is currently a major research thrust. In early years, most of the plantings

served as a food security crop, but human consumption now occupies only 10-20% of

production. About 30% is used as animal feed, much of it on-farm for chickens and pigs,

after chipping, drying and milling the roots. Industrial uses are on the increase as

Vietnam undergoes rapid economic development. Industry now absorbs about 30-40%

and this is rising. New varieties, mainly introduced from Thailand's breeding programs,

and diffused with help from large-scale starch processors, are gaining popularity,

especially in the South, for their high yield potential and high starch content. While

cassava data do not show this yet, it is expected that these new varieties will increase

yields significantly in the future. Cassava areas in Vietnam are shifting away from

(semi)urban zones towards "waste lands" and more marginal areas. Due to high industral

demand for cassava and changes in "land property" laws, the average cassava area (per

farmer) in the South is increasing.

PRODUCT AND MARKET TRENDS

Diversity is the defining characteristic of cassava products and markets in Asia,

both within and across countries. About 40% of cassava in the region is destined for

human consumption (FAOSTAT, 1997). In Indonesia, the level is about two-thirds. Most

of the remainder is processed for industrial purposes, principally chips for animal feed,

and starch. Raw roots are not traded on any significant scale. The initial processing

defines to some degree the market sector to which roots can be destined. This is unlike

the grains such as maize which are traded as whole, unprocessed grain, to be converted

into any number of products in the receiving country.

Fresh for Human Consumption

Outside of Kerala, India, and some poorer (isolated) districts of China and

Vietnam, nearly all cassava for food is first processed; direct consumption of baked or

boiled fresh roots is minor. This form of consumption is largely a rural practice, and

often by households having their own backyard garden. Fresh consumption will decline

with increasing incomes, urbanization, changes in dietary preferences and increasing

opportunity cost for cassava from emerging alternative (processed) cassava markets. It

must be noted, however, that cassava will remain a crop representing an on-farm reserve

emergency crop (for human consumption) in times of rice shortfall, as for example, has

been observed in Indonesia.

Chips and Pellets for Animal Feed

The cassava pellet industry peaked at the end of the 1980s. Since then total

volume has decreased, mainly affecting Thailand4 (Table 2, Figure 2). The reduced

exports to the European Union (EU) have only partly been offset by a concerted effort

to penetrate new, non-EU markets. During the early 90s a further shock was delivered

to EU-destined cassava exports, as a result of changes in the Common Agricultural Policy

(CAP), lowering internal EU feed grain prices. Nonetheless, although export prices (and

profits) have been reduced significantly, Thai pellets still can compete with EU internal

(barley) prices. Moreover, due to the 1997/98 baht devaluation, the pellet exports' price

edge will gain. It is doubtfull that pellet production will significantly rebound in the

future, since domestic competition for roots from the starch factories (who enjoy bigger

margins) is very strong.

Table 2. World trade of cassava products (chips, pellets and starch).

1992-94

Avg.

1994 1995 1996

World exports 9.8 7.2 5.4 6.4

-Thailand 8.3 5.9 4.1 5.0

-Indonesia 1.1 0.7 0.5 0.6

-China & Taiwan 0.3 0.4 0.4 0.4

-Others 0.1 0.1 0.4 0.4

World imports 9.7 7.2 5.4 6.4

-EU 6.5 5.2 3.2 3.8

-China & Taiwan 0.9 0.6 0.7 0.6

-Japan 0.5 0.3 0.4 0.4

-Korea, Rep. of 0.7 0.4 0.3 0.4

-Other 1.1 0.6 0.8 1.2

Source: FAO Commodity Market Review 1996-97

4 For a complete treatise on this subject, see Titapiwatanakun (1996), Henry and Gottret

(1996) and Hershey et al. (1997), among others.

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Figure 2. Exports of cassava products from Thailand between 1970 and 1995.

Source: Thai Tapioca Trade Association

Starch

Starch for industry is classified as native or modified. The technology for

modifying starches by physical, chemical or biological processes is highly advanced and

evolving rapidly, and modified starches are absorbing an increasing market share. Starch-

derived products include sweeteners (high fructose syrup, glucose syrup), dextrins,

monosodium glutamate, pharmaceuticals and various chemicals. Starch is used in large

quantities in the manufacture of paper, plywood, textiles, and as a filler/stabilizer in

processed foods. New products from starch are continually entering the marketplace.

Throughout the region, the industry is moving toward larger, more technologically

advanced plants, and small, less efficient factories are closing. Furthermore, an

increasing trend can be seen in Thailand, Vietnam and China of joint ventures with large

international companies from US, Europe, Taiwan, Korea, Japan, etc. Multinational food

11

companies with traditionally corn or potato starch based interest have started to

aggressively diversify into cassava starch manufacturing.

Thailand is leading the Asian starch boom (Figure 2), surpassing Indonesia in

recent years. Both export sales and domestic use have increased significantly. The focus

for exports has been on modified starches, partly for the larger profit margins and partly

to get around some of the import barriers imposed against native starch. Nonetheless, the

increase in starch exports has not nearly kept pace with the decline in pellet exports.

Private and public sectors are cooperating to identify and exploit internal growth markets

for starch as a complementary strategy to export-orientation.

Indonesia's starch production is utilized mainly in internal markets. Nearly two-

thirds goes into krupuk. Because of the specific starch characteristics required for this

product, maize starch is not a competitor. This gives some insulation from the

fluctuations of world starch prices. Growing demand in the near future is envisioned

from paper, cardboard and plywood industries. Both China and Vietnam have

significantly expanded and modernized their starch industries. Monosodium glutamate and

glucose are rapidly growing markets in both countries. Foreign investors are drawn to

the "newly opened" countries (Vietnam, Cambodia and Laos) to profit from the relatively

cheap factors of production, land and labor, to invest in large-scale starch industries.

Flour

Cassava flours come in many forms. The most common is gaplek in Indonesia.

Roots are peeled, chipped or sliced, and then dried. The dried chunks are ground or

milled to a meal, which is used in a wide array of food preparations. It is consumed

especially in times of rice scarcity, and partially substitutes for rice in rural daily diets.

Cassava flour may partially substitute for wheat flour in bakery and other products. This

is still minor in Asia, but is reported unofficially from several countries (Henry and

Gottret, 1996).

CASSAVA DEMAND PROJECTIONS

Thailand's continuing campaign to reduce its dependency on the European animal

feed market will dominate directions of the Asian cassava sector for the next decade. This

will take several forms: introducing new production technologies to keep prices

competitive with alternative energy sources; aggressively seeking new markets outside

Europe; development of internal feed markets; and further diversification into starch and

flour, with strong support for research on new processes and products. Other countries

of the region, once with aspirations to penetrate export markets for pellets, are now

recognizing that opportunities will depend very much on increasing production and

processing efficiencies.

Prospects for starch vary widely depending on the specific market. For native

starch, the different sources (maize, cassava, sweet potato, white potato) compete with

12

one another on the basis of price. The markets for specialized starch are rather uncertain.

On the one hand there is increasing demand, but on the other, there is a continually

evolving technology for modifying starches to meet specific product properties. Ostertag

(1996) suggests that most developing countries will use their resources most effectively

by first concentrating on developing internal starch markets, in order to reduce the risks

inherent in the export sector.

In a recent study of the major tropical root crops, Rosegrant and Gerpacio (1997)

of the International Food Policy Research Institute (IFPRI) have projected cassava

production and utilization in the year 2020, based on a model that takes into account

virtually all the world's food production and consumption (International Model for Policy

Analysis of Commodities and Trade (IMPACT). They foresee that moderate demand

growth for cassava products in Asia through 2020 will sustain viable cassava-based

development. The growth sectors vary within the region. In China, growth in feed

demand will be among the strongest anywhere, at 2.08% per year, accompanied by a

continuing trend for lower direct use as food. Southeast Asia should see healthy growth

in all sectors, i.e. 1.4% in food, 0.13% for feed, and a total of 1.25% (including

industrial use) (Table 3). The import demand in the non-cassava producing countries of

East Asia will rise at 1.0% per year, providing some additional market possibilities.

SECTOR CONSTRAINTS AND OPPORTUNITIES

Various factors will define cassava's potential as a catalyst for further evelopment

in Asia. These factors can be grouped in the domains of policy, market economics,

institutional issues and technology. However, the majority of important

constraints/opportunities deal with overlapping domains.

Policy

The policy arena more than any other will set the stage for cassava's role in Asia.

Both agricultural policy as well as broader economic policies impact the cassava sector.

Distortions in input and output markets, asset ownership, and other institutional and

market distortions adverse to the poor must be minimized. Government policy

interventions can be divided into direct (impacting on the cassava sector) and indirect

policies. The former includes fertilizer subsidies, credits, crop substitution schemes,

import tariffs and quotas, etc. The latter includes similar interventions but on other crops

(cassava substitutes or complements), that in turn will have an effect on the cassava

sector, such as interventions on feedgrains, foodgrains, etc. Furthermore, there exist

domestic and foreign policies. For Asian cassava sectors, history has shown that direct

and indirect foreign trade policies have had relatively more impact than any other

interventions. There is no indication that this will be significantly different in the future.

13

Table 3. Projected production and utilization of cassava" in 2020.

Growth rate for utilization Utilization Production

1993-2020 (%/veart in 2020 in 2020

Food Feed Total (million t) (million t)

China -1.27 2.08 1.19 3.9 4.2

India 1.00 0.00 1.00 7.6 7.8

Other East Asia -0.95 1.09 0.63 3.5 0.0

Other South Asia 1.00 0.00 0.83 0.6 0.6

Southeast Asia 1.40 0.13 1.25 27.0 51.1

Latin America 0.26 1.26 0.78 39.3 40.5

Sub-Saharan Africa 2.51 0.29 2.47 166.0 166.0

Developing 2.01 1.18 1.88 248.8 271.1

Liberalized trade has become the economic mantra of the 1990s. The watershed

Uruguay round of multilateral trade negotiations, under the auspices of the General

Agreement on Tariffs and Trade (GATT), is a fundamental influence on the direction of

the global economy. Trade liberalization will bring complex and unpredictable

adjustments in the agricultural sector. The implementation of regional trade agreements

is well-advanced in Asia. The Asia Pacific Economic Co-operation forum (APEC) has

18 members, which in total comprise half the world economy. Most of the major

cassava-producing countries of the region (excepting India) are members. APEC aims

to achieve free and open trade and investment by 2010 for its industrialized members and

by 2020 for the others. Hence, the future implications include decreased barriers within

the APEC trading bloc. This implies for example that protected markets like Japan,

would be more accesible for starch exports. On the other hand, EU policies continue to

evolve especially regarding Asian pellet exports, and this will be crucial for the future.

Careful monitoring, anticipation and timely actions are important.

Market Economics

Stabilizing or increasing demand in an environment of freer trade will depend on

the ability of the industry to respond quickly to shifts in product demand of traditional

markets, and analysis and subsequent penetration of new markets.

The overwhelming preference for rice as the starchy staple, and the increasing

demand for meat, will keep per capita cassava consumption levels low throughout Asia.

This growth in meat consumption, however, is the basis for projecting strong potential

14

to use cassava for on-farm feeding, or in balanced rations, for pigs and chickens.

Already, a clear increasing trend is identified of on-farm pig feeding (including cassava

chips or processing waste) in many sub-urban areas of southern China and Vietnam, to

satisfy the rapidly growing demand for pork in urban populations.

Cassava's competitive position in national and international markets is closely

linked to internal and world supplies and market prices of alternative commodities or

products. Because of cassava's versatility, it may compete with a range of products in

different markets. In the market for balanced feed rations, cassava in dried chip or pellet

form competes mainly with sorghum or maize, and sometimes barley. In world markets,

maize is the principal source of starch. In the principal cassava-producing countries of

Southeast Asia, rice, maize and cassava production all increased three to five-fold in the

past twenty-five years. Even this dramatic success, however, was not adequate for

supplying the food needs of growing and somewhat more affluent populations. Grain

imports, especially of wheat and maize rose from near zero in 1960 to 17 million tons

in 1995. The challenge for cassava products will lie in remaining competitive following

decreasing grain prices. This must be accomplished by reducing production and

processing costs, but especially the former. The current devaluation of many national

currencies in SE-Asia may have severe negative effects for their economic development,

but it may be a blessing in disguise for their cassava product exports.

Besides price, fortunately, specific intrinsic cassava starch characteristics

command a premium, or constitute an edge over potato or maize, in many upstream

modified starch-based products. Although these industries are extremely competitive and

secretive, they also can be very lucrative. The identification and penetration of these

markets will take a concerted technology and marketing R&D effort.

Infrastructure

Subsistence farming requires virtually no infrastructure, no need for purchased

inputs, and no need for highways for reaching markets. Commercial agriculture, on the

other hand, depends heavily on infrastructure. The World Bank notes that rapid economic

expansion and urbanization have outstripped the capacity of existing infrastructure, and

created serious impediments to further investments and growth. Insufficient electricity

generation capacity, outdated and inadequate telecommunications facilities, poor roads

and inefficient ports are the most crucial infrastructure problems. Purchased inputs for

agriculture are for the most part available, but may not be used on cassava because of

other constraints. There is little likelihood of major investment in infrastructure aimed

solely at supporting cassava development, but the general development of the region will

bring benefits to cassava production, processing and marketing.

Technology Development

Technology development includes the identification, generation and adaptation of

15

technology components suitable for alleviating the principal constraints of cassava

production, processing and marketing domains. Besides the alleviation of constraints,

technology must target opportunities that are presented through careful analysis.

Henry and Gottret (1996) and Van Norel (1997) analyzed and quantified the

principal cassava production constraints in Asia. Hershey et al. (1997) adapted and

summarized the results, shown in Table 4. Based on these and other findings, Table 5

shows an assessment of expected impact on (a) income, equity and food security, and (b)

the environment, by R&D intervention. As such, policy makers, investors and R&D

agencies can more specifically target desired technology options.

Technology Transfer

Technology transfer for cassava is often a bottleneck to achieving impact.

Transfer may fail either because the techniques are inappropriate or insufficient, or the

technology itself may not be acceptable. Both have had a significant role in Asia; both

are amenable to correction and improvement. In a well-functioning system, information

flows both ways between the producer and the user of new technology. It is in this sense

that technology transfer has an integrative function for the entire production, processing

and utilization system.

Technology transfer is normally considered an institutional function, the act of

moving technology from the hands of science to the fields or factories of end-users, by

a public extension service, or by private companies aiming at making a profit. Few of

the conventional resources or practices exist at adequate levels for cassava. Virtually all

programs in Asia report that extension services for cassava do not function optimally, and

some barely at all (CIAT, 1995). In this environment, many programs have used

unconventional and creative means to fill the gap left by institutional deficiencies.

The Department of Agriculture in Thailand uses three separate channels for its

highly successful transfer of new cassava varieties: direct transfer to farmers, mainly by

way of on-farm regional trials and demonstration plots; through chip and starch factories,

who promote new varieties to upgrade the quality of the raw product available; and the

more traditional extension service methods. In Indonesia and especially in Vietnam,

starch factories have also complemented the extension service to multiply and distribute

new varieties. India has the most structured technology transfer system, and in general

a better staffed public service sector than most countries. They have been able to achieve

impact both with new varieties and agronomic practices.

The cassava sector has the opportunity to be at the forefront of designing and

testing unconventional technology transfer systems. The lack of institutional resources has

already motivated public and private partnerships, and an array of other means to get

technology to end-users. A survey of methods that have succeeded and those that have

failed, and brainstorming about future planning, could be a highly useful exercise for

Asia, and with implications elsewhere.

16

Table 4. Cassava constraints analysis for Asia, with comparison to global".

Yield Total Total Total

gain in Area yield yield yield

Constraints affected affected gain gain gain as %

area(%) (%) (%) ('000 tons) of global2)

Soil Management 35 17,067 36

Low soil fertility 32 68 22 10,690 32

Soil erosion 17 60 10 5,039 43

Surface temperature 11 26 3 1,338 62

Crop Management 21 10,291 22

Sub-opt. land preparation 8 33 3 1,262 22

Quality of planting material 17 48 8 3,958 19

Inadequate spacing 8 47 4 1,853 30

Weeds 18 37 7 3,218 23

Intrinsic varietal traits 24 11,384 31

Low yield potential vars. 26 89 24 11,384 31

Climate 11 5,153 25

Drought 16 58 9 4,496 26

Low winter temperature 0 8 1 658 54

Diseases 2 929 3

Root rots 6 5 0 151 5

Bacterial blight 6 19 1 553 6

Anthracnose 2 15 0 132 5

ICMV 6 3 0 92 1

Other leaf/stem pathogens 0 82 2 1,042 30

Pests 3 1,478 7

Green and red spider mites 6 38 2 1,112 9

Mealybug 2 2 0 16 0

Whitefly 4 3 0 51 10

Termites 2 3 0 33 5

Mammalian pests 5 2 0 46 3

Scale insects 5 9 0 211 52

Tipacola plagiata 11 0 0 9 100

Total potential production increase 96 46,301 23

Post-harvest 21 9,923 32

Quality 22 60 13 6,390 31

Processing 15 24 4 1,806 30

Product marketing 20 18 4 1,727 47

Total cassava sector 116 56,224 24

11 Other constraints with near zero potential yield gain are excluded from the table.

* Total yield gain in Asia as percent of global yield gain.

Source: adaptedfrom Henry and Gottret, 1996.

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19

Integrating the System and the Actors

Basic economic theory and experience show that changes in production,

processing and marketing of cassava need to be integrated and coordinated to provide

broad benefits across the system. Increased production in a constrained market simply

depresses prices for producers. Expanded markets without ability to increase production

capacity can restrain market growth due to excessive price increases. New or more

efficient processing may be needed to fit the demands of new markets, or to process

increased volumes of raw materials. Unless the integration of these phases are anticipated

during the technology development process, the products of research and development

will not be implemented in an optimal manner.

Both producers and consumers hope for some imbalance in the supply/demand

dynamics. Naturally, these hopes extend in different directions, i.e. producers want

excess demand to raise farm-level prices, and consumers hope for excess supply to

depress prices. At the same time, both recognize their own long-term financial health

depends on that of the other, i.e. supply and demand are in dynamic balance.

Even though the markets for cassava are much better developed in Asia than in

either Africa or Latin America, attention to the continued balance in production,

processing and marketing is warranted. The integration of actors - R&D institutions,

farmers, processors, marketers and consumers — does not always develop optimally in

a laissez faire atmosphere. The integrated project experiences in Latin America are a

valuable lesson with high potential for application in Asia as production systems and

markets undergo rapid changes (Ospina et al., 1996).

Instutional Aspects

While the preceeding section treats the integration of stakeholders at the sector

level, a similar integration is required at the the institutional level. Who are the main

players or stakeholders here? They include foremost: national governments, (national and

international) R&D agencies and networks, extension services, private sector, NGOs,

farmer/processor/trader associations or representative bodies, and donor agencies.

Because of different goals, several of these stakeholder groups may have different

priorities and interests. However, the challenge lies in integrating these different actors

around a common cause and action agenda, whereby individual tasks should be divided

according to relative comparative advantages. A case in point is the on-going IFAD

spearheaded Global Cassava Strategy process. Since 1996, a series of activities co-

conducted by a large variety of principal cassava stakeholders (national and international)

are gearing towards the formulation and implementation of a globally acceptable co-

owned cassava strategy. As such, the final (end of 1998) result is expected to be a

common cassava agenda (globally and regionally) that will be shared and acted upon by

actors on the demand side (demands and opportunities of the sectors) and the supply side

(governments, R&D agencies, networks, donors, ...).

20

Information Management and Communications Technology

Asia as a whole has relatively advanced communications systems. This can have

a large impact on integrating the components of a research and development system,

especially if policymakers, researchers, development specialists, farmers, processors,

marketers, and industry managers are all linked together. The internet makes this possible

in ways that were not remotely possible just a decade ago. A very important use of the

internet is to diffuse information regarding technology, technology generators and

diffusers, farm and market products, volumes and prices, financing opportunities, etc.

On the one hand, improved and timely information diffusion will strengthen marketing

efficiency and technology diffusion, on the other hand, it offers an opportunity to better

integrate (supply and demand of) the different actors in the cassava arena.

REFERENCES

CIAT. 1995. Cassava Breeding, Agronomy Research and Technology Transfer in Asia. R.H.

Howeler (Ed.). Proc. 4th Regional Workshop, held in Trivandrum, India. 2-6 Nov. 1993.

CIAT. 1996. Annual Report. Project 2. Improved Cassava Gene Pools. CIAT, Cali, Colombia.

32 p.

FAOSTAT. 1998. http://www.fao.org//giews/

Food and Agriculture Organization (FAO). 1997. Food Outlook. Various issues. FAO, Rome.

Henry, G. and V. Gottret. 1996. Global Cassava Trends: Reassessing the Crop's Future. CIAT

Working Document No. 157. CIAT, Cali, Colombia. 45 p.

Hershey, C, G. Henry, R. Best, K. Kawano, R. Howeler, and C. Iglesias. 1997. Cassava in

Asia - Expanding the Competitive Edge in Diversified Markets. Regional review.

Global Cassava Strategy. International Fund for Agricultural Development (IFAD), Rome,

Italy.

Ospina, B., S. Poats and G. Henry. 1996. Integrated cassava research and development projects

in Colombia, Ecuador, and Brazil: an overview of CIAT's experiences. In: D. Dufour, G.M.

O'Brien and R. Best (Eds.). Cassava Flour and Starch: Progress in Research and Development.

CIRAD/CIAT, Cali, Colombia, pp. 333-357.

Ostertag, C.F. 1996. World production and marketing of starch. In: D. Dufour, G.M. O'Brien

and R. Best (Eds.). Cassava Flour and Starch: Progress in Research and Development.

CIRAD/CIAT, Cali, Colombia, pp. 105-120.

Rosegrant, M.W. and R.V. Gerpacio. 1997. Roots and tubers in the 21" century: their role and

importance in the global food market. IFPRI discussion document. IFPRI, Washington, D.C.,

USA.

Titanapiwatanakun, B. 1996. Thai Cassava Starch Industry: Its Current Status and Future

Potential. In: D. Dufour, G.M. O'Brien and R. Best (Eds.). Cassava Flour and Starch:

Progress in Research and Development. CIRAD/CIAT, Cali, Colombia, pp. 55-70.

Van Norel, J.G. 1997. Priority setting for research and development in cassava. An assessment

of needs of cassava production and post-harvest sectors in Latin America and Asia. Mimeo.

CIAT, Cali, Colombia, Oct. 1997.

21

PROGRESS IN CASSAVA BREEDING AT THE CHINESE ACADEMY

OF TROPICAL AND AGRIC. SCIENCES (CATAS)

Lin Xiong, Li Kaimian, Zhang Weite and Huang Jiex

ABSTRACT

During the past 16 years the Chinese Academy of Tropical and Agricultural Sciences

(CATAS) has made good progress in developing improved cassava varieties for China. Several

improved varieties have been released in south China, of which cv. SC124, with high yield and

good cold resistance, is already being planted on a large scale, mainly in Guangxi and Yunnan

provinces. SC8002, which is characterized by a high yield potential and tolerance to cold, has

mainly been released in Guangdong province, while SC8013, with high yield and good wind

resistance, is being multiplied for planting in the typhoon affected areas of Hainan and Zhanjiang

district of Guangdong. The release of these new varieties will improve the present situation of

dependence on only two varieties, and will promote varietal comparisons, as well as stimulate the

development of cassava production in China.

In recent years, a large F, population and its progeny clones have been produced from

true seeds, which were mainly introduced from CIAT/Colombia and from the Thai-CIAT

program. Up to 1995, a series of breeding materials with different characters have been evaluated

and selected; out of these, three new varieties have been released, more than 30 accessions have

been used as cross parents, and 15 promising clones have been recommended for testing in

Regional Trials. In 1996, 316 clones were tested at the Single-row Trial, 63 clones were further

evaluated at the Preliminary Yield Trial, and 54 clones were included in the Advanced Yield

Trials. Most of the clones in the Regional Trial and the Advanced Yield Trial were characterized

by high yield and high dry matter content (especially clones OMR33-10-4 and OMR34-1 1-3 have

very high dry matter content); their performance at the later stages is closely being watched.

Also, some good clones were selected from the Preliminary Yield Trial in 1995/96, such as

ZM9315, ZM93255, ZM9317,ZM93236etc., andOMR36-63-6,OMR36-40-9,OMR36-05-9etc.

from the Single-row Trial; these showed significantly higher yields compared with the check

variety, SC205, while their root dry matter contents were higher than 40%, the harvest indices

were over 0.62 and they had good wind resistance.

High-yield, high dry matter content and good wind resistance are still our major

objectives in cassava breeding. From our experience we are convinced that it is impossible to

make any major breakthrough in our breeding program by just using our native genetic resources.

There are two ways for us to realize our objectives in the future: 1) selection from the

hybridizations between our local germplasm and those from CIAT/Colombia or the Thai-CIAT

program, such as ZM9036, ZM8803, ZM9057 etc.; and 2) the comprehensive evaluation and

direct selection of the seed materials introduced from CIAT/Colombia or the Thai-CIAT program.

While the importance of the former scheme is increasing, up to now, many of the good clones

with high yield, high dry matter content and high harvest index were selected from this latter

source. As such, the materials introduced from CIAT/Colombia or the Thai-CIAT program and

their hybrids with the local genetic materials are playing an important role in cassava varietal

improvement in China.

INTRODUCTION

Cassava is the fourth most important crop in southern China, following rice,

sugarcane and sweet potato. It is used mainly as animal feed and for starch

Chinese Academy of Tropical & Agricultural Sciences (CATAS), Danzhou, Hainan, China.

22

manufacturing, which both play an important role in the agricultural economy. Cassava

production makes full use of available land resources, especially in upland and hilly

areas, as well as in marginal areas with poor soils. In recent years, cassava production

and its economic value have increased due to the rapid development of the animal feed

and starch industry, as well as to improvements in marketing channels for cassava

products. More and more attention has been paid to the release and planting of new

varieties and the use of good cultivation technologies. Considerable progress has been

made in cassava varietal improvement at the Chinese Academy of Tropical and

Agricultural Sciences (CATAS), with CIAT's cooperation and support. A national

cassava network, including cassava breeding, selection, testing and extension, has been

established. New varieties, such as SC124, SC8002 and SC8013 have been released in

different regions of the country because of their high yield potential. In addition, many

promising clones are constantly being selected from F, seedling populations and from

their progenies. Some of these with high yield, high root dry matter content and wide

adaptability will be further tested, and when approved, will be released and extended as

new improved varieties in the future.

VARIETAL IMPROVEMENT AT CATAS

Collection, Evaluation and Utilization of Cassava Germplasm

In China, all cassava varieties that are now planted at a large scale were

introduced from abroad. Some local clonal progenies, which had evolved through natural

or artificial selection from natural crosses, also exist, but these are very limited and

scattered, with less than 20 accessions in total. Therefore, cassava germplasm in China

can mainly be attributed to direct introductions or to cross breeding of local with

introduced germplasm. Over the years, CATAS has introduced more than 30 accessions

from CIAT/Colombia or from the Thai-CIAT program, and a number of cross parents

from CIAT's breeding materials have also been evaluated and are now being conserved.

A cassava germplasm bank has been set up at CATAS, which presently has more than

120 accessions; their major characteristics have been evaluated, and are being catalogued

and documented. This forms the foundation for cassava breeding and is a source of

genetic diversity for selecting cross parents. From the materials of CIAT/Colombia or

the Thai-CIAT program, a group of special germplasm has been evaluated and selected:

Nanzhi 188 and CM3044-2 were found to be male-sterile, CM3993-9 and SM614-1 have

high dry matter content, while MCol 22 and CM 1585- 13 are characterized by short plant

height, wind-resistance and abundance of female flowers. Thus, materials from CIAT

or the Thai-CIAT program have not only played an important role in cassava breeding,

but are also a useful genetic resource in China. CATAS has developed some promising

clones, such as ZM9036, ZM9057, ZM9079, ZM9111, ZM9315 etc, through

hybridization between local materials with those from CIAT or from the Thai-CIAT

program.

23

Multiplication and Extension of Improved Varieties

With the further development of the animal feed and starch processing industries,

as well as the starch-based chemical industry, demand for cassava roots have dramatically

increased in China. Therefore, the release and rapid multiplication of improved varieties,

so as to increase cassava yields, is very important to satisfy producers' and consumers'

needs. CATAS has bred and recommended new varieties, such as SC124 and SC8002,

which have high yield and are Cold tolerant, as well as SC8013 with high yield and wind

resistance. These varieties have been tested and released in Guangdong, Guangxi,

Hainan and Yunnan provinces.

In recent years, the new variety SC124 was mainly released in Guangxi and has

also been introduced and recommended to Jiangxi, Guizhou, and Sichuan provinces. It

is estimated that in 1995 a total of 8000 ha were planted with this variety. In 1992,

SC124 was also introduced into the districts of Honghe, Yuxi and Simao of Yunnan

province to be demonstrated in a total area of 1.6 ha under different soil conditions; this

resulted in a significant increase in yield. According to the report of the Cassava Feed

Resource Development and Utilization Group of Jinping County of Yunnan, its average

yield was 45 t/ha, while the highest yield was 85.7 t/ha, which was about three times

higher than that of the local variety. This was mainly attributed to the high yield

potential of this variety in regions that are not affected by typhoons. Up to 1996, SC124

has been extented to 6775 ha in Yunnan province only.

In 1994, the improved varieties SC8002 and SC8013 from CATAS were

recommended for further testing and release in China. Results of tests and

demonstrations at different locations over the years indicate that both SC8002 and

SC8013 have high yield potential and wide adaptability (Table 1). SC8002 had an

average yield of 33.7 t/ha in 12 locations, outyielding the check varieties SC205 and

SC201 by about 22 and 36%, respectively. The leaf life of SC8002 was 5.8 and 5.9

days longer than those of SC205 and SC201 , respectively (Table 2). Meanwhile, its cold

resistance was only slightly lower than that of SC124. This variety has been further

tested and released in Guangdong, Guangxi, Hainan and Yunnan provinces with a

potential extension area of 4000 ha. However, the planted area in 1996 was estimated

at 1300 ha.

The new variety SC8013 has very good wind resistance and had a mean yield of

37.9 t/ha in nine different locations, outyielding SC205 and SC201 by about 38 and 53%,

respectively. Its leaf life was 6. 1 and 6.2 days longer than those of SC205 and SC201 ,

respectively (Table 2). In addition, its dry matter content was higher than those of the

check varieties. This is a breakthrough in breeding for wind resistance in China, as it

provides a good possibility for high and stable yields of cassava also in typhoon affected

areas. It will be further extended in Hainan and in Zhanjiang district of Guangdong with

a potential area of 3400 ha, of which 600 ha will be planted in 1996. This variety is now

being tested for rapid multiplication using the shoot propagation system.

24

Regional Trials of Promising Clones

CATAS has established a national cassava network in China, including

experiment stations in Guangdong, Guangxi and Hainan provinces, to conduct the

Regional Trials. During 1992-1995, 22 promising clones have been evaluated in

Regional Trials, and those found to have high yield and wide adaptability, such as

OMR33-10-4, ZM9036, ZM9057, SM1542-3 and SM1592-3 have been selected for

further testing (Table 3).

Table 1. Fresh root yield (t/ha) of SC8002 and SC8013 in comparison with those of

two local varieties in different regions of southern China.

Location SC8002 SC8013 SC205 SC201

Hongxing State-farm, Guangdong

Lecheng Agri-technical station, Guangdong

Qiongzhong, Hainan

Fengshun, Guangdong

Qinzhou, Guangxi

Wuxuan, Guangxi

Dingan, Hainan

Wuming, Guangxi

Zengcheng, Guangdong

Boluo, Guangdong

Guangning, Guangdong

Jiexi, Guangdong

Zijin, Guangdong

Baisha, Hainan

Nanning, Guangxi

Guilin, Guangxi

CATAS

31.7

33.8

31.7

30.6

30.7

33.4

36.4

43.8

49.5

22.5

23.3

37.0

36.6

46.3

58.5

40.2

20.2

57.6

26.0

22.5

33.2

24.1

29.7

31.5

30.0

19.7

28.8

21.4

21.3

41.5

26.4

28.9

20.6

11.7

44.4

23.9

30.0

21.4

15.5

Among the clones listed in Table 4, SM1592-3 and SM1542-3 are progenies from

the F) population of 1992, and their yields were the highest among 24 clones that were

included in the Advanced Yield Trial in 1994. Root dry matter contents of these two

clones were above 38%. Results of the Regional Trials conducted in 1995 again indicate

that these two clones showed good yield performance; they need to be further evaluated

in the future. OMR33-10-4, ZM9036 and ZM9057, which are clonal progenies from the

F, population of 1990, also continued to show high yield potential and high root dry

matter content under different conditions over the years (Tables 4 and 5).

25

Table 2. Leaf life and various root characteristics of SC8002 and SC8013 in

comparison with those of two local cassava varieties as determined in

different regions of southern China.

Variety Average Fresh root RDMC" Starch HCN

leaf life yield (%) content (mg/kg)

(days) (t/ha) (%) (fresh wt.basis)

SC8002 77.9 33.7 38.6 29.9 44.6

SC8013 78.2 37.9 41.9 32.0 32.5

SC205 72.1 27.5 38.1 30.2 63.4

SC201 72.0 24.7 37.7 30.3 128.2

"RDMC= root dry matter content.

The weight of roots of Fj seedlings OMR33-10-4, ZM9036 and ZM9057 were

3.8, 5.8 and 4.3 kg, respectively. They have shown good performance and stable high

yields as well as high root dry matter contents at the CATAS experimental station.

During 1992-1995, their average yield were 34.4, 19.8 and 20.9% higher than SC205,

respectively. Of these clones, OMR33-10-4 has a significantly higher yield potential than

SC205, outyielding the latter by up to 78% in term of dry yield; also, it has better wind

resistance. This clone was selected by farmers who participated in the FPR project at the

pilot sites of Hainan. It is therefore being further propagated, hoping that it will become

a new variety with high yield and good quality (high RDMC) in south China.

Evaluation and Selection of Clones

For more than 16 years CATAS researchers have been cross breeding cassava.

From 1992 to 1995 CATAS introduced and produced 560 cross parents as well as 23,060

true seeds, of which 17,477 seeds and 216 parents came from CIAT/Colombia and the

Thai-CIAT program. From these, 11,092 plants have been produced for the F,

population and 1648 good plants have been selected. In 1996, 316 clonal selections were

included in the Single-row Trial, 63 clones in the Preliminary Yield Trial, 54 clones in

the Advanced Yield Trial, and 15 promising clones were recommended to be further

tested in Regional Trials throughout southern China.

26

Table 3. Average results of evaluations of promising cassava clones in Regional

Trials conducted in varions locations during 1992-1995.

Clones No.of Fresh root Dry root Root dry matter

locations yield(t/ha) yield(t/ha) content(%)

ZM9057 6 38.2 14.5 38.0

SM 1592-3 8 37.6 13.5 36.0

ZM9036 5 32.8 12.8 39.1

OMR33-10-4 6 29.4 11.7 39.7

SMI 542-3 6 27.8 1-0.1 36.4

SC205 6 28.1 10.9 38.9

SC201 5 28.3 10.3 36.5

Table 4. Average fresh and dry root yields of three promising clones in comparison

with those of the check variety SC205 in Regional Trials conducted in 1992

to 1995.

Clones 1992 1993 1994 1995

Fresh Dry Fresh Dry Fresh Dry Fresh Dry RDMC

(t/ha) (t/ha)i (t/ha) (t/ha) (%)

OMR33- 10-4 30.8 12.7 41.9 16.1 28.1 10.8 23.8 9.0 38.3

ZM9036 24.1 10.4 31.3 12.3 28.1 11.1 24.2 9.6 39.6

ZM9057 27.0 11.3 33.6 12.6 31.2 11.6 23.6 8.6 37.2

SC205 23.7 8.5 31.4 11.6 21.0 8.0 23.8 8.3 36.6

Table 5. Fresh root yields (t/ha) of three promising clones and of the local check

varieties in Regional Trials conducted in different locations. Data are

average yields for 1992 to 1995.

Locations OMR33-10-4 ZM9036 ZM9057 SC205 SC201 SC102

Baisha, Hainan 28.1 36.0 34.0 25.5 - -

Qiongzhong, Hainan 43.5 47.0 66.3 52.6 - -

Dingan, Hainan 24.4 20.6 23.8 - - 10.0

Xuwen, Guangdong 35.0 - 31.0 28.9 - -

Lurong, Guangxi 25.3 16.1 24.5 - 13.6 -

Nanning, Guangxi 18.5 20.9 13.1 - 16.6 -

Wuxuan, Guangxi 31.7 55.4 28.6 35.0 - -

Danzhou, Hainan 28.1 25.4 24.2 25.3

27

Results of the Advanced Yield Trial in 1994 and 1995 indicate that some good

clones, such as OMR34-11-3, SM1542-3, SM1691-3, ZM9111, ZM9244, ZM9281 etc,

which were selected from Preliminary Yield Trials in 1993 and 1994, showed higher

yield potential compared with SC205 (Table 6); of these, OMR34-11-3, SM1542-3 and

ZM9111 had better comprehensive characteristics. Especially OMR34-11-3 has good

plant type, high harvest index, high RDMC, good wind resistance, while both its yield

and RDMC were the highest in the Preliminary Yield Trial of 1993 and the Advanced

Yield Trial of 1994. It is a very interesting clone. ZM9079, ZM9066, ZM9045 etc,

also showed very high yield potential, but these will need to be further tested. Some

clones with high RDMC, such as ZM9315, ZM9317, ZM93255, ZM93236, OMR36-63-

6, OMR36-40-9 and OMR36-05-9 were selected from the Single-row and Preliminary

Yield Trials in 1995 (Tables 7 and 8).

Table 6. Yield parameters and other characteristics of lines selected from the

Advanced Yield Trial conducted in CATAS in 1995.

Clones Dry root Fresh root RDMC Plant Root

yield(t/ha) yield(t/ha) (%) type shape

OMR34-11-3 10.7 27.3 39.2 4.5 4.0

ZM92157 10.0 29.4 34.1 4.0 4.0

ZM9266 9.6 27.5 34.8 5.0 3.5

SMI595-2 9.6 31.6 30.5 5.0 5.0

ZM9111 9.5 28.4 33.5 5.0 4.3

SM1691-3 9.1 25.0 36.5 5.0 4.5

SM 1542-3 8.4 23.8 35.3 5.0 4.3

SC205 8.2 23.2 35.6 5.0 4.0

DISCUSSION

Breeding Efficiency Using Germplasm of Different Origin

All breeding materials used at CATAS originated from CIAT/Colombia, the

Thai-CIAT program, or from locally produced true seeds. The material from

CIAT/Colombia showed a wide genetic variability and, in general, had very strong vigor

with early and prolific branching. Many high yielding clones, such as CM4031-2 and

CM4040-1 were produced from this material; however, in general, their root dry matter

content was low. But in recent years, some of these clones are characterized by high

yield as well as high RDMC, such as SM1542-3, SM1592-3 and SM1691-3.

Undoubtedly, these materials will always be an important source of genetic variability for

cassava breeding programs in China.

From our experience in recent years, we believe that the materials from the Thai-

CIAT program have shown over the years a high selection efficiency and a very high

28

RDMC, whether they are individuals or populations. The two promising clones,

OMR33-10-4 and OMR34-1 1-3, are typical representatives of this. Seven clones were

selected from the Single-row Trial of 1995, of which five clones originated from this

material (Table 8). Among the 17 clones with more than 40% RDMC, a harvest index

of more than 0.60, and strong resistance to wind, 13 came from Thai-CIAT materials.

This is a very clear indication that the materials from the Thai-CIAT program have

shown a very high selection efficiency. They will play an ever more important role in

cassava varietal improvement in China, especially in increasing cassava root dry matter

content.

Table 7. Yield parameters and other characteristics of lines selected from the

Preliminary Yield Trial conducted at CATAS in 1995.

Clones Dry root Fresh root RDMC" Harvest Plant Root

yield(t/ha) yield(t/ha) (%) index type shape

ZM93253 11.4 33.8 33.7 - 5 4

ZM9315 11.3 28.1 40.2 0.48 3 3

ZM93255 11.0 27.3 40.5 0.48 2 3

ZM9317 10.9 27.5 39.7 0.54 3 4

ZM93236 10.5 28.2 37.4 0.51 5 4

SC205 10.1 27.7 36.3 0.50 3 3

" RDMC = root dry matter content

The locally produced materials can not be ignored, as they are still an important

resource for cassava breeding in China. But it is very difficult to make any breakthrough

by using only the limited native genetic resources. Therefore, in order to widen the

genetic variation and make faster progress, a combination of utilizing native germplasm

with those coming from abroad, so as to produce better cross parents, should be most

successful. Some elite clones, such as ZM9036, ZM91 11, ZM9315, ZM9137, ZM93253

and ZM93236 were selected from the hybrids between the native materials with those

introduced from CIAT/Colombia or the Thai-CIAT program. Obviously, the materials

from CIAT/Colombia and Thai-CIAT will be an indispensable source of germplasm, and

these will greatly affect the impact of cassava breeding in China, both now and in the

future.

29

Table 8. Yield parameters of lines selected in the Single-row Trial conducted at

CATAS in 1995.

Clones Dry root Fresh root RDMC Harvest

yield(t/ha) yield(t/ha) (%) index

OMR36-63-6 17.1 40.4 42.3 0.63

OMR36-05-9 14.4 35.4 40.8 0.67

OMR36-40-9 13.4 32.0 41.8 0.59

ZM9454 12.8 30.0 42.5 0.52

OMR36-11-3 12.6 36.0 35.0 0.55

OMR36-05-7 12.3 33.8 36.4 0.63

ZM9495 12.2 34.0 35.9 0.57

SC205" 12.1 34.4 35.2 0.61

''the highest yield in the Single-row Trial

Relationship Between Root Yield, Harvest Index, Biomass and Root Dry Matter

Content

As Dr. Kawano has stated, "cassava harvest index is hereditary, and there is a

close relationship between root yield and harvest index". From Figure 1 we can see that

cassava root yield in CATAS was strongly and positively related to harvest index. It

means that high yielding clones can usually be selected from those having high HI and

strong vigor.

Biomass is a function of the clone's native vigor, but is also seriously affected

by the soil and climatic conditions. Kawano (1987) reported that both biomass and

harvest index were naturally very important to fresh root yield, especially in poor soils.

Figure 2 shows that there was a strong positive correlation between fresh root yield and

biomass under the conditions of CATAS. That means that low biomass production or

low HI immediately disqualifies any clone from the selection. Yet, either high biomass

or high HI alone are not a guarantee for high yield, especially at very high yield levels.

Thus, only a good combination of these two characters can lead to high yields.

Root dry matter content of cassava is also an hereditary character, but has no

clear relationship with fresh root yield. However, from Figure 3 we can see that fresh

root yield and RDMC are not contradictory characters either. This means that selection

for both high yield and high RDMC is a realistic objective. Our experience at CATAS

has proven this point, i.e., clones having both high yield and high RDMC have been

selected, such as OMR33-10-4, OMR34-11-3, ZM9036, ZM9111 and ZM9315.

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REFERENCES

Chinese Academy of Tropical Agric. Sciences (CATAS). 1995. Research of Tropical Crops.

Volum 2, pp. 33-42. (in Chinese)

Chinese Academy of Tropical Agric. Sciences (CATAS). 1992. Cassava Research in China. Proc.

of 2nd National Cassava Workshop in China, held Oct 19-24, 1992, in CATAS, Hainan,

China. pp. 19-46. (in Chinese)

Chinese Academy of Tropical Agric. Sciences (CATAS). 1992. Proc. of Hainan Crops

Germplasm Resources Investigation. Nov, 1992. pp. 33-38. (in Chinese)

Kawano, K. 1987. Inherent and environmental factors related to cassava varietal selection. In:

C.H. Hershey (Ed.). Cassava Breeding: A Multidisciplinary Review, Proc. ofa Workshop held

in the Philippines, March 4-7, 1985. pp. 207-226.

34

CASSAVA VARIETAL IMPROVEMENT AND DISSEMINATION IN GUANGXI

Tian Yinong and Lee Jun1

ABSTRACT

The Guangxi Subtropical Crops Research Institute (GSCRI) began their cassava varietal

introduction and improvement program in 1981. Since 1985, GSCRI has introduced cassava

hybrid seeds as well as promising clones by tissue culture from CIAT/Colombia, from the Thai-

CIAT program, as well as from other institutes. Through continuous selection and experiments,

several promising clones, such as SM1113-1, SM1600-1, CM5443-1, SM1741-8 etc. have been

identified, and these have been tested to a certain extent in on-farm trials. Since their release and

dissemination these clones have awakened great interest by both farmers and starch factories.

Some of them have now spread to other provinces. In China, high yield and high starch content

of cassava varieties are still the most important factors in raising the comprehensive benefits

resulting from cassava production. This is also the only way to change the stagnated position of

cassava production, which in the past increased mainly by increasing the area planted. At the

moment, many local governments of the principal cassava growing areas are conscious of this and

have started to spend money on the introduction and dissemination of new higher-yielding

varieties.

INTRODUCTION

In recent years, the cassava planting area and total production in Guangxi

province of China have greatly increased (Table 1), the average annual rate of increase

from 1991 to 1995 being 6.4 and 17%, respectively. This is the result of the continuous

development of cassava processing, the products of which have had a good market. In

many areas farmers have adopted new cropping systems and have increased their

production investment, resulting in an increase in cassava root yield, as well as the

income derived from growing cassava (Tables 2, 3 and 4).

The cassava growing area in Guangxi is mainly concentrated in Yulin, Wuzhou,

Nanning and Liuzhou districts, which are located in the middle and eastern parts of the

province (Figure 1). The cassava area and production in these four districts account for

55 and 50% of the total in Guangxi, respectively, and the cassava processing industry is

also mainly established in these areas, except for Yulin district. The natural conditions

in these areas are comparatively favorable and communications are well-developed. But

they also have a solid industrial foundation, so these areas developed rapidly and all these

districts belong to the economically developed areas of Guangxi. But, being a low-value

crop, cassava is also partly being replaced by other crops. Thus, the main cassava area

in Guangxi seems to be moving to the western and northern parts from the eastern and

middle parts (Figure 2). The data of cassava area for the most recent years in different

districts of Guangxi have shown this. The western and northern parts of Guangxi include

the two districts of Baise and Hechi; these are mainly hilly and mountainous areas, with

low fertility soils and poor natural conditions, so they are the two less-developed districts

Guangxi Subtropical Crops Research Institute, Nanning, Guangxi, China.

35

of Guangxi. For a long time there were very few processing factories and farmers

planted cassava usually on steep slopy land without any investment in production, so that

yields were very low. The roots were mostly used for feeding livestock. In recent

years, the government has given some "assistance projects" to this area and several starch

(or alcohol) factories were built one after another, while some cassava production bases

have been set up. They have introduced some new cassava varieties and adopted new

production technologies, so the yield of cassava increased markedly. Compared with

1990, the cassava area in these two districts in 1995 had increased more than 20,000 ha,

and total production increased 356,106 t. They account for 34% of the total increase in

area and 18% of the total increase in cassava production in Guangxi. In 1995, the

cassava area and production in these two districts accounted for 17.5 and 15% of the total

in Guangxi, respectively, while in 1990 this was only 12 and 12%.

Cassava Varietal Improvement at the Guangxi Subtropical Crops Resarch Institute

(GSCRI)

SC201 and SC205 are the two most important varieties, which are estimated to

account for 85% of the total cassava growing area in Guangxi. These two varieties were

introduced into Guangxi about 60 years ago. Since cassava has not been an important

commodity in the past, farmers did not pay any attention to adopt new varieties or new

production technologies. This is the reason that yields in Guangxi were low for a long

time. In the 1980s, although several new cassava varieties were introduced, few of these

were really adapted to the conditions of Guangxi. Because only 1-2 cassava varieties

were used until the beginning of the 1990s, there was little potential to increase farmers'

income. Moreover, the harvest period is short and is mainly concentrated in Dec and

Jan, so except in these two months, only dried chips can be used for processing. In view

of this, many starch factories appealed to agricultural institutes to introduce or improve

new cassava varieties with high yield and high starch content, and they have been willing

to fund some of the research.

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Table 2. The yield and gross income from planting different cassava varieties in

Laibin county of Liuzhou district, Guangxi, China in 1995.

Fresh root

yield

(t/ha)

Price

roots

(yuan/t)

Stem

yield

(t/ha)

Price Gross

stems income

Variety (yuan/t) (yuan/t)

SC201 (local) 22.5 360 25.4 200 13,180

SC205*(new) 26.3 370 21.5 430 18,976

SCI 24 (new) 30.0 360 25.6 1100 38,960

* SC205 is a new variety for Laibin county but is common in southern Guangxi

Table 3. Comparison between several crops in terms of gross and net income in

Laibin county of Liuzhou district Guangxi, China in 1995.

Yield Price Gross income Net income

(t/ha) (yuan/t) (yuan/t) (yuan/t)

Cassava 22.5 360 8,100 3,600

Orange 22.5 1900 42,750 33,000

Sugarcane 60.0 270 16,200 7,200

Mango 7.5 3200 24,000 16,800

38

Table 4. Comparation between several intercropping systems in terms of gross

income in Laibin county of Liuzhou district, Guangxi, China in 1995.

Cassava fresh Price Intercrop Price Gross

root yield roots yield intercrops income

(t/ha) (yuan/t) (t/ha) (yuan/t) (yuan/ha)

Cassava+Watermelon 22.5 360 30.0 400 20,100

Cassava+ Peanut 24.8 360 1.9 3,200 15,008

Cassava+ Watermelon seeds2 1.8 360 0.5 14,000 14,848

Source: Laibin State Farm

The Guangxi Subtropical Crops Research Institute (GSCRI) began their cassava

varietal introduction and improvement program in 1981 . At that time, they were mainly

working on the introduction of promising clones or new varieties from other Chinese

institutes, which were tested in the Institute and then distributed to State Farms. Since

1985, GSCRI has introduced cassava hybrid seeds as well as promising clones by tissue

culture from CIAT/Colombia, from the Thai-CIAT program, as well as from other

institutes. In the last decade, GSCRI has introduced a total of 23,733 cassava hybrid

seeds from 432 parent combinations (Table 5).

In consideration of the natural conditions of cassava production in Guangxi and

based on the demands from farmers and starch factories, the general objectives of the

cassava varietal introduction and improvement program in Guangxi are to develop

promising clones with the following characteristics:

- High root yield and high harvest index

- High root starch content

- Non-branching growth habit

- Tolerance to wind

- Good root shape

- Early harvestability

During the past ten years, GSCRI has made good progress in developing

improved cassava varieties (Table 6). Through continuous experimentation and selection,

four promising clones have now been identified, i.e. SMI 113-1, SM1600-1, CM5443-1

and SMI 74 1-8 (Table 7). These four promising clones were higher yielding than the

local varieties SC201 or SC205 at three locations (Nanning, Mingyang and Laibin). The

yields of clone SMI 1 13-1 at Nanning, Mingyang and Laibin were 23.2, 52.5 and 28.4

t/ha, respectively. The yields of clone SM 1600-1 at Nanning and Laibin were 24.9 and

39

40.7 t/ha, respectively. The yields of clone CM5443-1 at Nanning and Laibin were 29.5

and 34.0 t/ha, respectively; and the yields of clone SMI74 1-8 at Nanning and Laibin

were 32.2 and 36.0 t/ha, respectively. The root dry matter content of clone SMI 1 13-1

is also very high (Table 8).

Cassava Varietal Dissemination in Guangxi - Channels and Procedures

The channels for cassava varietal dissemination in Guangxi are as followed:

- Committee of Science and Technology

- Extension Station of Agricultural Technology

- State Farm (starch factory)

- New Technology Development Company

- Private enterprises

As the department responsible for science and technology, the Committee of

Science and Technology is not only in charge of carrying out policies of the government

in the countryside, but also plays a very important role in disseminating the achievements

of science and technology. It is the key unit for spreading new technologies from

scientific institutes to rural areas. The local Extension Station of Agricultural

Technologies is the unit responsible for spreading agricultural technologies directly to

farmers, but normally they work by introducing new high yielding technologies to

agricultural communities.

State Farms are separate units with all these functions. There is an Agricultural

Research Team (ART), which is composed of technical staff whose members have

graduated from an Agricultural School or University (College). State Farms tend to have

a lot of land. So, in general, State Farms are not only a good experimental site, but are

also an ideal place for scaling-up agricultural production. Trials conducted in State

Farms normally conform to the standard.

New Technology Development Company is a new organization, which has

expanded rapidly in recent years; most of these are operated by the government and are

especially engaged in the introduction and dissemination of technologies.

The private entrepreneurs are people who achieve success during the rapid

development of a modern economy; among them are many who are operating in

agricultural production. They are not only businessmen but also producers, and they

have not only capital but also flexible management strategies which allows them to easily

adopt new things and take advantage of their conditions to quicken the tempo of

agricultural development.

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Table 5. Number of cassava hybrid seeds supplied by CIAT to GSCRI in Guangxi, China,

from 1985 to 1996.

No. of No. of Source

Year seeds crosses

1985 1,500 30 CIAT/Colombia


1987 - - -



1990 3,350 59 CIAT/Colombia, Thai-CIAT program







Total 23,733 432

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44

Table 7. Promising clones selected at GSCRI in Nanning, Guangxi, China, from

1987 to 1995.

Clones Parents Main features

SMI 1 13-1 MCol 2215 high yield, high starch content, good plant type, high HI

SM1600-1 MPar 126 high yield, high HI, good plant type

X3 high yield, good plant type, high HI

CM5443-1 MBra 35xCM523-7 high yield

SM1741-8 MPar59 high yield

Table 8. Yield and oner traits of promising clones in GSCRI in Nanning, Guangxi,

China, 1992-1994.

Fresh root Root DM Dry root Harvest

Clones yield content yield index

(t/ha) (%) (t/ha)

SM1113-1 23.2 39.5 9.2 0.65

SM 1600-1 24.9 34.3 8.5 0.64

X3 22.7 32.4 7.4 0.66

SC201 (local) 20.0 36.5 7.3 0.54

SC124(new cv.) 22.4 35.5 8.0 0.57

45

The procedures for cassava varietal dissemination in Guangxi are shown in

Figure 3. The Guangxi Subtropical Crops Research Institute normally disseminates

improved cassava clones through State Farms or starch factories (most starch factories

are owned by State Farms). Promising clones are first sent to the representative State

Farms (mostly located in the eastern, southern or middle part of Guangxi, but also in the

northern part) to conduct on-farm yield trials. An agronomist from the Agriculture

Research Team (ART) is appointed by the Farm to be responsible for the trial; data on

cassava biological characters are taken regularly. During the harvest, the whole staff of

the ART comes to evaluate the trial in the field. The characters evaluated include: fresh

root yield, starch content, plant type, root shape, harvest index, germination, wind

tolerance, etc. In the second year, the experiment is expanded. During the harvest the

local government invites representative farmers from nearby villages to participate in the

field day and to evaluate the new varieties. Then, these farmers may take some planting

material of the selected varieties to be multiplied and planted in a demonstration trial in

their own villages, so as to step-by-step disseminate these to other growers. Another case

is as follows: since the harvested roots are mainly for selling to starch factories, there is

a special relationship between farmers and starch factories. Actually, farmers get much

informations and advice about growing cassava from starch factories; in other words, the

farmers trust the starch factory. So it should be affirmed that the dissemination of

cassava improved varieties through starch factories is one of the most rapid and effective

channels.

Distribution of Promising Clones Selected by GSCRI

Since 1994 GSCRI has successfully recommended several promising cassava

clones to farms and starch factories. In 1994, GSCRI cooperated with Mingyang starch

factory, the biggest cassava starch factory in China, in conducting a Regional Yield Trial

at the State Farm in which the factory is located. The results show that SMI 113-1

produced a very high yield of 52.5 t/ha in a sandy clay soil, 53% higher than that of

SC205; and the starch content of SMI 113-1 was 2% higher than that of SC205. In

March, 1995, upon the invitation of Laibin State Farm, we set up an On-farm Yield Trial

there. From the time of planting until harvest, the leadership of this Farm attached great

importance to the trial. On Dec 1995, with the support of CIAT and the Guangxi Starch

Association, we held a very successful "field day" on cassava varietal improvement.

More than 40 participants (mainly farmers) from farms, institutes, starch factories, etc.

attended the field day. They carefully evaluated all promising cassava clones in this trial

in terms of yield, starch content, plant type, harvest index, wind tolerance, etc. The

results of this trial indicate that some new cassava clones, such as SMI 1 13-1, SM 1600-1,

etc. not only produce higher fresh root yields but also have a higher starch content than

SC201, which is the most important variety that has been used in Guangxi for a long

time. Other biological characters, such as plant type, root shape, etc., were also better

46

than SC201 . All the participants, including specialists of the Guangxi Starch Association

and fanners, highly appreciated the progress made by the GSCRI cassava program.

After this field day, many farms and starch factories in Guangxi province wanted to

introduce these cassava clones. In 1996 we distributed these clones to Xingan county in

the north, to Qinzhou city in the south and to Baise in the northwestern part of Guangxi,

as well as to Shimao and Zhenyuan of neighboring Yunnan province.

We believe that the identification of above-mentioned promising clones will

greatly help the development of the cassava starch industry in Guangxi, as well as the

development of the agricultural economy of these mountainous areas. Since their release

and dissemination, these clones have awakened great interest by both farmers and starch

factories and even by the government. As of 1996, the national Ministry of Agriculture

and the Guangxi provincial Science and Technology Committee have supported programs

on cassava varietal improvement and dissemination at GSCRI. In view of the history and

the present situation of cassava production in China, high-yielding and high-starch content

cassava varieties are still the most important factors in raising the comprehensive benefits

resulting from cassava production. This is also the only way to change the stagnated

position of cassava production, which in the past increased only by increasing the area

planted. At the moment, many local governments of the principal cassava growing areas

are conscious of this and have started to spend money on the introduction and

dissemination of new higher-yielding varieties.

REFERENCES

Lu Rongjun. To establish the trading system of cassava and promote the development of the

cassava industry in Guangxi. (in Chinese)

Tian Yinong, Lee Jun, Zhang Weite and Fang Baiping. 1995. Recent progress in agronomy

research in China. In: R.H. Howeler (Ed.). Cassava Breeding, Agronomy Research and

Technology Transfer in Asia. Proc. 4th Regional Workshop, held in Trivandrum, Kerala,

India. Nov 2-6, 1993. pp. 195-216.

Zhang Weite, Lin Xiong, Li Kaimian, Huang Jie, Tian Yinong, Lee Jun and Fu Quohui. 1997.

Cassava agronomy research in China. In: R.H. Howeler (Ed.). Cassava Breeding, Agronomy

and Farmer Participatory Research in Asia. Proc. 5th Regional Workshop, held in Danzhou.

Hainan, China. Nov 2-8, 1996.

11

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48

BREEDING AND VARIETAL IMPROVEMENT IN THAILAND

Jarungsit Limsila1, Atchara Limsila1, Watana Watananonta1 and Kazuo Kawano2

ABSTRACT

In Thailand cassava breeding is the responsibility of the Rayong Field Crops Research

Center of the Department of Agriculture (DOA), and of Kasetsart University (KU). From 1975

to 1992, six cultivars have been released for industrial use, i.e. Rayong 1, Rayong 3, Rayong 60,

Rayong 90, Sri Racha 1 and Kasetsart 50. All these recommended cultivars are widely adopted

by farmers, but the area planted with improved cultivars was increasing only slowly due to the

low multiplication rate of cassava. Therefore, in 1992 the Government approved the allocation

of 1 1 million US dollars for the DOA and the Department of Agricultural Extension (DOAE) to

rapidly multiply stakes of those cultivars and distribute those to the farmers, in order to replace

about 240,000 ha of Rayong 1 with new high-yielding cultivars by the year 1996. According to

the most recent survey by DOAE, this target has been well accomplished before the end of the

project period.

During the past three years, the cassava breeding program in Thailand continued to

emphasize selection for high yield and high dry matter content, as well as some other desirable

traits, especially high total plant weight and harvest index, and good plant type, germination and

survival under stressful conditions. One of our successes has been the release of another industrial

cultivar, Rayong 5, in October 1994. Rayong 5 is superior to Rayong 1 in many aspects. It has

been well adopted and is spreading rapidly in many parts of the country.

For Thai cassava breeders it seems to be increasingly more difficult to produce new

clones that can surpass the exellent cultivars KU 50 and Rayong 5; however, some of our new

clones, such as CMR33-57-81 and CMR33-53-181 appear quite promising, and CMR33-57-81

may be released as Rayong 7 in the next 2-3 years.

INTRODUCTION

Cassava in Thailand is produced mostly for export in the form of hard pellets,

chips and starch, and the major markets are in the EU countries. During the past ten

years (1985-1994) there has generally existed a situation of overproduction, since the

demand for cassava roots was less than 20 million tons, while the supply was usually

over 20 million tons. The Government was well aware of this problem and became even

more concerned when the EU's CAP Reform was gradually implemented between 1993

and 1995. In 1992, the Thai Government established the policy to reduce the cassava

planting area from 1.5 million ha to 1.28 million ha by encouraging farmers to replace

cassava with fruit trees, fast growing trees, pastures and livestock.

In 1995 the area under cassava was reduced to 1.3 million ha and the production

was only 18 million tons. However, contrary to expectations, the cassava root price went

up to 1.20 baht per kilogram, which had never happened before. It looked as if the

Government had been successful in reducing the cassava planting area, but in fact the

drastic decline in cassava area was a direct result of the low cassava root price during the

1 Rayong Field Crops Research Center, Huay Pong, Rayong, Thailand.

2 CIAT, Dept. Agriculture, Chatuchak, Bangkok, Thailand.

49

previous two years, 1993 and 1994. In response to the attractive price of cassava in

1995, it can be predicted that the cassava planting area will rapidly increase again after

this year.

While the Government tried to decrease the cassava planting area during the past

few years, at the same time it encouraged farmers to change from the local cultivar,

Rayong 1, to the newly released cultivars, in order to improve the efficiency of

production. The Department of Agriculture (DOA) and the Department of Agricultural

Extension (DOAE) of the Ministry of Agriculture and Cooperatives initiated a five year

project, starting in 1992, to rapidly multiply stakes of the improved cultivars and to

distribute these to the farmers. The project's target is that Thailand will have an area

under new improved cultivars of about 240,000 ha by the year 1996. According to the

DOAE statistics, this target has already been accomplished during the 1995/96 planting

season. The national average yield is expected to increase from 13.75 t/ha to 14.68 t/ha

at the end of the project.

CASSAVA VARIETAL IMPROVEMENT

Background

Since 1975 and until 1992, the Rayong Field Crops Research Center of the Field

Crops Research Institute of DOA, and Kasetsart University (KU) have released six

cultivars for industrial use and one cultivar for direct human consumption. The

background and the outstanding characteristics of those cultivars are described in Table

1.

Breeding Objective

The main objectives of cassava breeding in Thailand is to improve root yield and

dry matter content (or starch content) in order to satisfy the needs of the farmers and the

factories. It was suggested by Kawano (1988) and Rodjanaridpiched et al. (1995) that

cassava yields should be improved through the simultanious improvement of total biomass

and harvest index. Aside from the above important characteristics, the following

characteristics are also our breeding and selection criteria:

- early harvestability

- good plant type (tall and non- or less-branching)

- good stake quality (germination and storage duration)

- good root shape with white flesh

- tolerant to major pests and diseases

50

Table 1. Background and outstanding characteristics of seven released cultivars.

Cultivar

Year

Released Parents

Background and outstanding

characteristics

Rayong 1 1975 unknown

Rayong 3

Rayong 60

1983

1987

Sriracha 1

Rayong 90

Kasetsart 50

Rayong 2

1991

1991

1992

1984

(F) MMex 55

(M) MVen 307

(F) MCol 1684

(M) Rayong 1

(F)MCol 113xMCol22

(M) Rayong 1

(F) CMC76

(M) V43

(F) Rayong 1

(M) Rayong 90

(F)MCol 113

(M) MCol 22

Selected from local land race.

Exellent agronomic traits. Relatively

high yield. Moderately resistant to

major pests and diseases. Well adapted

to low inputs.

Selected from CIAT Fl hybrid seeds.

High dry matter content.


High fresh yield. Recommended for

early harvesting. Excellent agronomic

trails.

Selected from KU Fl hybrid seeds.

Excellent agronomic traits. High dry

matter content.

Selected from DOA Fl hybrid seeds.

High dry matter content. Relatively

high yield.

Selected from KU Fl hybrid seeds.

High yield and high dry matter content.

Well adapted to unfavorable conditions.


Recommended for human

consumption. Relatively high yield, and

carotene andvitamin A contents. Low

HCN content.

Recent Progress

During the past three years, the DOA has released one industrial cultivar called

Rayong 5, and has tested two promising clones, i.e. CMR33-57-81 and CMR33-53-181,

in farmers' fields.

Rayong 5, previously identified as CMR25-105-112, was obtained from a cross

between 27-77-10 and Rayong 3, made in 1982 at the Rayong Field Crops Research

Center. It was released by DOA on October 28, 1994. It is one of the attempts to

improve cassava cultivars through an improvement of the top parts along with the roots.

Table 2, in which data from hundreds of trials are compiled, indicates that Rayong 5 is

51

higher in total plant weight and harvest index, and has higher root yields than Rayong

1, Rayong 3, Rayong 60 and Rayong 90.

Rayong 5 is now widely adopted by cassava growers due to its high yield and

other outstanding properties, such as ease of harvest due to its good root shape and root

formation, good germination and drought tolerance. Table 3 shows the yields of Rayong

5 when planted in the early rainy season and in the late rainy season, compared with

those of Rayong 1 . Its fresh root yield, dry root yield and dry matter content were

higher than those of Rayong 1 by 20, 31 and 9% in the early rainy season plantings,

respectively. For the late rainy season plantings, its fresh root yields was higher than

Rayong 1 by 28% , partly due to the better survival of plants of Rayong 5 during the dry

season.

Promising clones

It seems to be increasingly more difficult for Thai cassava breeders to create new

cassava clones that are superior to the already existing excellent cultivars Kasetsart 50

and Rayong 5. However, two promising cassava clones, CMR33-57-81 and CMR33-53-

181, were selected by the Rayong Field Crops Research Center staff from crosses made

in 1990.

Table 2. Yield parameters of Rayong 5 compared with all previously released cultivars. Data

from Regional Yield Trials and On-farm Trials conducted from 1988 to 1993.

R5 Rl R3 R60 R90 KU50

Top yield (53 trials)

Total plant weight (t/ha)

Leaf and stem weight (t/ha)

Harvest Index

Root yield (120 trials)

Fresh root yield (t/ha)

-Relative to Rl (%)

Dry matter content (%)

Dry root yield (t/ha)

-Relative to Rl (%)

39.8 38.6 30.1 37.4 37.3 39.4

14.3 16.2 11.1 13.8 13.7 14.6

0.64 0.58 0.63 0.63 0.63 0.63

27.6 22.7 19.9 26.5 24.7 25.3

121 - 88 117 109 HI

34.8 32.3 35.3 32.5 36.0 35.5

9.7 7.4 7.1 8.7 8.9 9.1

131 - 96 117 120 123

52

Table 3. Average yield of Rayong 5 and Rayong 1 when planted in the early rainy season and

in the late rainy season from 1988 until 1993.

Rayong 5 Rayong 1 % Relative to Rl

26.9 22.5 119

34.8 31.8

9.4 7.2 130

29.0 22.6 128

35.0 33.2

10.3 7.7 134

Early rainy season planting (78 experiments)

Fresh root yield



Late rainy seaon planting (42 experiments)




CMR33-57-81 was obtained from a cross between Rayong 1 and Rayong 5, while

CMR33-53-181 was obtained from crossing OMR26-14-9 with Rayong 1 . The progenies

were evaluated in eight Regional Trials and in 15 On-farm Trials during the 1994/95 and

1995/96 seasons. The trials were conducted in two major cassava planting areas of the

country, the Northeastern region (Nakon Ratchasima, Khon Kaen, Maha Sarakarm,

Kalasin, Roi Et, Mukdahan and Sakhon Nakon provinces), and the Central Region

(Rayong, Chonburi, Chantaburi, Prachinburi and Suphanburi provinces).

The data from 11 trials in the Central Region and 12 trials in the Northeastern

Region during the 1994/95 and 1995/96 seasons are presented in Table 4. Considering

the fresh root yield, dry matter content, dry root yield, total biomass and harvest index

of the two promising clones and the check varieties, i.e. Rayong 1, Rayong 90 and

Rayong 5, from each region and the average of the two regions, the following

conclusions could be drawn:

-CMR33-57-81 and CMR33-53-181 produced higher fresh root yields, dry root yields

and total biomass than Rayong 1 , Rayong 90 and Rayong 5 in both regions, while

maintaining a high harvest index at the same level as that of Rayong 5.

-CMR33-57-81 performed excellently in the Northeastern Region, while CMR33-53-181

performed very well in the Central Region.

-The root dry matter contents of the two promising clones are higher than that of Rayong

1, but not as high as those of Rayong 90 and Rayong 5.

CMR33-57-81 and CMR33-53-181 are now in the On-farm Trials and are

expected to be released specifically for each region in the next 2-3 years.

Activities through CIAT

Since 1985 the DOA has provided cross-pollinated (CMR) and open-pollinated

(OMR) F, seeds to CIAT for distribution to other cassava producing countries in Asia.

53

From 1985 to 1993 74,568 F, seeds were provided to CIAT and another 27,570 seeds

were provided during the past three years (Table 5). Kawano (1993) indicated that the

Thai breeding materials were well-adapted to the semi-arid and seasonally dry lowland

tropics; therefore, they are offering excellent selection opportunities in most national

cassava breeding programs in Asia.

Table 4. Fresh root yield, dry matter content, dry root yield, total biomass and

harvest index of CMR33-53-181 and CMR33-57-81 compared with check

varieties in Regional and On-farm Trials during 1994/95-1995/96.

Central Northeastern

Region Region Average


(1 1 trials) (12 trials) (23 trials)

CMR33-53-181 32.9 32.0 32.4

CMR33-57-81 28.9 36.0 32.6

Rayong 1 24.3 25.4 24.9

Rayong 5 27.4 28.5 28.0

Rayong 90 28.1 24.9 25.2


CMR33-53-181 31.9 34.4 33.2

CMR33-57-81 31.3 34.8 33.2

Rayong 1 30.0 32.9 31.5

Rayong 5 33.3 35.4 34.4

Rayong 90 34.2 34.6 34.3


CMR33-53-181 10.3 11.1 10.7

CMR33-57-81 9.0 12.6 10.9

Rayong 1 7.1 8.6 7.9

Rayong 5 9.0 10.2 9.6

Rayong 90 8.5 8.8 8.6

Total biomass (t/ha)

CMR33-53-181 44.6 52.7 49.0

CMR33-57-81 37.8 55.1 47.2

Rayong 1 39.0 46.7 43.2

Rayong 5 37.4 49.3 43.9

Rayong 90 37.8 44.0 41.1

Harvest Index

CMR33-53-181 0.69 0.63 0.66

CMR33-57-81 0.72 0.67 0.69

Rayong 1 0.60 0.56 0.58

Rayong 5 0.69 0.61 0.65

Rayong 90 0.67 0.59 0.63

54

In May 1995, Thailand had an opportunity to be the host of a Workshop on

Cassava Breeding Methods and Practices, organized by CIAT for Asian cassava

researchers. The workshop provided the participants with ample opportunities for

learning from the Thai varietal improvement and dissemination programs and for sharing

experiences among each other.

Table 5. Number of cassava Fl hybrid seeds exchanged between CIAT and the DOA.

Year Number of seeds

Hybrid seeds introduced from CIAT

Hybrid seeds provided to CIAT

1975-1993 137,448

1994 9,843

1995 11,964

1996 9,781

Total 169,036

1985-1993 74,568

1994 7,678

1995 11,223

1996 8,669

Total 102,138

REFERENCES

Kawano, K. 1988. CIAT cassava germplasm development in Asia - Cooperation with National

Programs. In: R.H. Howeler (Ed.). Cassava Breeding and Agronomy Research in Asia. Proc.

2nd Regional Workshop, held in Rayong, Thailand. Oct 26-28, 1987. pp. 117-126.

Rodjanaridpiched, C, A. Limsila, D. Supraharn, O. Boonseng, P. Poolsanguan, C. Thiraporn

and K. Kawano. 1995. Recent progress in cassava varietal improvement in Thailand. In: R.H.

Howeler (Ed.). Cassava Breeding, Agronomy Research and Technology Transfer in Asia.

Proc. 4th Regional Workshop, held in Trivandrum, Kerala, India. Nov 2-6, 1993.

pp. 124-134.

55

VARIETAL IMPROVEMENT AND DISSEMINATION BY KASETSART

UNIVERSITY, THE THAI TAPIOCA DEVELOPMENT INSTITUTE,

AND THE DEPT. OF AGRICULTURAL EXTENSION

Chareinsuk Rojanaridpichect , Somporn Phongvutipraphan2, Piyawuth Poolsanguan3

Kaival Klakhaeng*, Vichan Vichukit1 and Ed SaroboP

ABSTRACT

For decades a cassava yield stagnation has been observed in Thailand. In addition,

current prices of cassava roots and products are highly fluctuating, as they depend on the

European Union market's price of cereals, the subsidy of which will be relaxed and will soon

disappear. Since 1992 the Thai government has been implementing a policy of reducing the

cultivated area, while maintaining the quality and total production of cassava, by the replacement

of the traditional local variety, Rayong 1 , by higher yielding new varieties. The objective of this

paper is to describe the varietal improvement of cassava by Kasetsart University (KU), as well as

the cooperative multiplication and dissemination of new, improved cultivars to farmers by KU,

the Thai Tapioca Development Institute (TTDI) and the Department of Agricultural Extension

(DOAE). Two popular cassava cultivars, Kasetsart 50 and Rayong 5, were officially released in

1992 and 1994, respectively. Subsequent breeding efforts at KU have concentrated on the cross

between Rayong 5 and Kasetsart 50. The preliminary results shows that several F, clones from

the cross had potential dry root yields 10-30% higher than those of the parents. These promising

clones have harvest indices and root starch contents similar to those of the parents, but have a

significantly higher total biological yield.

Regarding varietal dissemination, in 1994 KU produced 750,000 long stems, and in 1995

1.5 million long stems of Kasetsart 50, for the DOAE to distribute to cassava fanners for further

multiplication and distribution. Participating farmers received free cassava stems and 15-15-15

fertilizer at the rate of 625 kg/ha. In 1994, the multiplication area was 5,440 ha involving 2,458

farmers from 25 provinces. Additionally, in 1995, there were 3,899 participating farmers from

22 provinces, who multiplied cassava in 6,274 ha.

In 1993, the TTDI was founded as a foundation, with an initial trust fund of US$24

million. Later, in 1995 TTDI cooperated with KU in distributing 1.79 million stems of Kasetsart

50 to 1,198 cassava farmers from 11 provinces, while 5.97 million stems of Kasetsart 50 and

484,000 stems of Rayong 5 were distributed in 1996 to 4,243 cassava farmers from 23 provinces.

Subsequently, in 1995, farmers who planted Kasetsart 50 indicated very satisfactorily performance

of this new variety. An average yield of 26.47 t/ha was obtained by 26 surveyed fanners who

planted Kasetsart 50, as compared with the national average yield of 14.6 t/ha.

INTRODUCTION

Thailand is the world's leading cassava pellet and starch exporter. Around 4.7-

7.3 million metric tons of cassava pellet, and about 500,000-700,000 tons of starch were

exported during 1990-1994. The major importer of cassava pellets is the European

1 Dept. of Agronomy, Kasetsart University, Bangkok, Thailand.

2 The Thai Tapioca Development Institute, Huay Bong, Nakorn Ratchasima, Thailand.

3 Sri Racha Research Station, Kasetsart University, Sri Racha, Chonburi, Thailand.

* Department of Agricultural Extension, Bangkok, Thailand.

56

Union (EU). Since 1993 the EU has started to reduce the high support price of its

cereals; this will inevitably reduce the price of Thai cassava roots in the EU market.

In order to safeguard the Thai cassava farmers two policies have been launched.

First, to decrease the cassava planted area by replacing cassava with fast-growing trees,

fruit trees and pastures, and secondly, to increase cassava productivity through cultivar

replacement. The traditional Rayong 1 cultivar is to be replaced with new, high-yielding

cultivars, such as Kasetsart 50 and Rayong 5.

Two institutes have conducted cassava breeding research, i.e. the Rayong Field

Crops Research Center (RFCRC) under the Field Crops Research Institute (FCRI) of the

Department of Agriculture (DOA), Ministry of Agriculture and Cooperative (MOAC),

and Kasetsart University (KU). Besides the farmers own efforts, a large-scale

multiplication, promotion and distribution project has been conducted by both the

Department of Agricultural Exptension (DOAE) and the Thai Tapioca Development

Institute (TTDI). Since 1994, the adoption rate of new cassava cultivars has been

increased at a dramatic rate.

VARIETAL IMPROVEMENT BY KASETSART UNIVERSITY

RFCRC is the major Center for cassava breeding in Thailand. Several new

varieties have been released by RFCRC, namely, Rayong 1 in 1975, Rayong 3 in 1983,

Rayong 60 in 1987, Rayong 90 in 1989, and Rayong 5 (formerly called CMR25-105-

112) in 1994. The breeding program at Kasetsart University is relatively small.

Nevertheless, the variety Sriracha 1 was released in 1990, and in cooperation with

RFCRC and the Centro Internacional de Agricultura Tropical (CIAT), Kasetsart 50 was

released in 1992. Details of these varieties were summarized by Rojanaridpiched et al.

(1995).

Rayong 1 is a selection from a local land race. It has excellent agronomic triats,

such as good germination, vigorous vegetative growth, favorable plant type, moderate

harvest index (HI), tolerance to mites, and the capacity to give relatively high yields

under average farmer conditions. More than 1 million ha were planted with Rayong 1

every year. Thus, it can be stated that Rayong 1 is the most successful cassava variety

in the world, and the success of the Thai cassava industry is largely due to the excellent

characteristics of Rayong 1 (Limsila et al., 1992).

Several breeding strategies have been proposed since 1985. Tan (1987) suggested

that the goal of cassava yield improvement was to improve HI while maintaining the

same canopy strength of traditional cultivars. In addition, Kawano (1988) showed that

a simultaneous improvement in HI and total biological yield (TBY) in these genotypes

would result in higher yield than those of presently available cultivars, both in high and

low-yielding environments. Later, Kawano et al. (1990) showed that further

improvement in HI and TBY were possible. Rojanaridpiched et al. (1995) tested the new

cultivars, Rayong 3, Rayong 60, Rayong 90, Rayong 5 and Kasetsart 50 in comparison

57

with Rayong 1 in 53 locations during 1991 and 1992. Rayong 3, which had higher HI

but lower TBY than Rayong 1, yielded higher than Rayong 1 only in very high- yielding

environments. Rayong 60 and Rayong 90, which had higher HI and similar TBY to

Rayong 1, yielded higher in high-yielding environments, but in low-yielding

environments Rayong 60 yielded lower, while Rayong 90 yielded higher than Rayong 1 .

Kasetsart 50 and Rayong 5, which had higher His and TBYs yielded higher than Rayong

1 in all environments.

Kasetsart 50 and Rayong 5 are popular cultivars because of their higher fresh root

yields and higher root starch contents than Rayong 1, while their plant types are as

vigorous as that of Rayong 1. Since the release of kasetsart 50 in 1992 and Rayong 5

in 1994, the breeding objective at KU has been to breed for new clones with higher yield

than Kasetsart 50 and Rayong 5, while maintaining the root starch content and other

agronomic triats equivalent to, or better than, these two cultivars.

Since the KU breeding program is not so large, that breeding effort has been

concentrated on the cross between Rayong 5 and Kasetsart 50. The two cultivars were

derived from different parents; therefore, in-breeding effect should not occur. The

pedigree of Kasetsart 50 and Rayong 5 are as follows:

cultivars pedigrees

Kasetsart 50 Rayong 1 x Rayong 90

Rayong 5 27-77-10 x Rayong 3

Rayong 90 CMC76 x V43

27-77-10 CM321-170 x MCol 1684

Rayong 3 MMex 55 x MVen 307

The cross between Rayong 5 and Kasetsart 50 was made in 1991/92. The first

year selection from 963 seedling plants (seedling selection) was based on plant type, root

yield, root starch content and HI. Consequently, 204 plants were selected in 1992/93 at

Sriracha Research Station. For the second year selection, each selected plant or clone

was planted in a Single-row Trial at Sriracha Research Station in 1993/94. Selection was

based on the same criteria as the seedling selection with additional consideration on root

shape (compact roots) as a criterion for ease of harvest. A total of 108 clones were

selected. These 108 clones were preliminarily tested at Huay Bong Station of TTDI in

Nakhon Ratchasima. This preliminary yield test of 108 clones was split up into several

sets. Each individual set consisted often clones with three additional check cultivars, i.e.

Rayong 1, Rayong 5 and Kasetsart 50, and was replicated twice. Several clones had

higher root yield and total plant weight than Rayong 1, Rayong 5 and Kasetsart 50, while

maintaining as high a root starch content and HI as Rayong 5 and Kasetsart 50 (Table

1). A total of 28 clones were selected.

These 28 selected clones were grouped and tested in farmers' fields during

58

1995/96. Yield data are shown in Tables 2 to 4. Even though each promising clone was

tested in only one location, the performances of several clones were very encouraging.

When compared with the traditional cultivar Rayong 1, dry root yields of several

promising clones were 39-1 13% higher than that of Rayong 1. In the last decade, it has

been difficult to find any clones that yielded higher than Rayong 1. All of these

promising clones were the F[ from the cross between Rayong 5 and Kasetsart 50. These

two parents have several good chareteristics, such as high root yield, starch content, HI

and TBY. The dry root yield of MKUC34-114-206 was 38% higher than that of

Kasetsart 50 (Table 2), while that of MKUC34-1 14-54 was 25% higher than that of

Kasetsart 50 (Table 3), and that of MKUC34-1 14-85 was 12% higher than that of

Rayong 5 (Table 4).

Table 1. Yield data of some selected clones harvested at 12 months after planting

from a Preliminary Yield Trial at Huay Bong, Nakhon Ratchasima in

1994/95.

Clones Fresh root Root starch HI Total plant

yield content weight

(t/ha) (%) (t/ha)

Set I

MKUC34-1 14-187 50.4 24.7 0.53 95.2

MKUC34-114-206 34.2 24.5 0.50 68.6

Rayong 5 33.5 23.2 0.49 68.9

Kasetsart 50 21.1 21.6 0.41 51.7

Rayong 1 16.0 10.0 0.28 56.5

Set II

MKUC34- 114-200 39.2 26.8 0.54 72.7

MKUC34-1 14-175 39.6 21.5 0.57 69.6

Rayong 5 37.0 23.7 0.53 69.6

Kasetsart 50 30.6 23.8 0.53 57.3

Rayong 1 21.7 18.6 0.36 60.5

Set III

MKUC34-1 14-54 33.1 23.3 0.43 76.4

Rayong 5 39.2 24.5 0.57 68.6

Kasetsart 50 30.0 24.4 0.31 66.6

Rayong 1 23.3 16.7 0.38 74.2

59

Table 1. (continued)

Clones Fresh root Root starch ]HI Total plant

yield content weight

(t/ha) (%) (t/ha)

Set 6

MKUC34-114-17 41.2 24.9 0.4787.5

Rayong 5 26.7 27.0 0.5449.0

Kasetsart 50 29.8 26.1 0.5554.0

Rayong 1 26.5 15.9 0.3674.0

Set 7

MKUC34-1 14-84 52.8 22.5 0.6877.8

MKUC34- 114-85 41.5 20.5 0.5575.4

MKUC34-114-64 38.1 22.0 0.5175.2

Rayong 5 32.5 25.6 0.5163.7

Kasetsart 50 38.1 23.2 0.5766.7

Rayong 1 32.5 15.9 0.4277.2

Table 2. Yield data of some promising clones planted at Sriracha Research Station

in 1995 and harvested at 10 months after planting.

Clones Root yield (t/ha) Root starch

content

l)) (%)

HI Total plant weight

fresh dry (% of R, (t/ha) (roofR,")

MKUC34-114-206 23.31 8.13 187 22.6 0.69 34.12 144

MKUC34-1 14-200 21.85 7.25 167 20.4 0.66 33.10 140

MKUC34-1 14-175 19.02 6.30 145 20.3 0.65 29.29 124

MKUC34-114-187 19.20 6.04 139 18.0 0.59 32.05 136

Kasetsart 50 17.36 5.89 135 21.3 0.63 27.58 117

Rayong 5 14.77 4.80 110 19.5 0.68 21.58 91

Rayong 1 15.76 4.34 100 12.8 0.67 23.54 100

LSD(P<0.05) 5.89 1.85 - 1.13 0.06 8.06 -

CV(%) 18.09 17.61 - 3.37 5.61 16.15 -

l)R, = Rayong 1

60

Table 3. Yield data of some promising clones planted at Huay Bong, Nakhon

Ratchasima in 1995 and harvested at 9 months after planting.


content

") (%)


fresh dry (% of R, (t/ha) (%ofR,")

MKUC34-114-54 23.86 8.53 213 23.7 0.59 40.75 149

MKUC34-114-64 23.58 8.35 208 23.1 0.62 36.85 135

MKUC34- 114-84 22.40 8.11 202 24.3 0.64 34.35 126

MKUC34- 114-206 21.16 7.50 187 23.2 0.59 35.33 129

Kasetsart 50 19.16 6.80 170 23.0 0.54 35.05 128

Rayong 5 17.06 6.00 150 22.8 0.56 30.60 112

Rayong 1 12.66 4.00 100 18.1 0.47 27.21 100

LSD (P< 0.05) 6.34 2.42 - 3.14 - 8.58 -

CV(%) 24.66 26.61 - 9.58 - 18.40 -

%=Rayong 1

61

Table 4. Yield data of some promising clones planted at Khonburi, Nakhon

Ratchasima, in 1995 and harvested at 8 months after planting.


content

'') (%)


fresh dry (96 of R, (t/ha) (ftofR,1*)

MKUC34-114-85 28.23 9.78 197 22.2 0.64 43.89 160

MKUC34-1 14-17 25.64 9.21 185 23.9 0.55 46.48 169

Rayong 5 24.86 8.71 175 22.4 0.61 41.01 149

Kasetsart SO 21.25 7.71 155 24.5 0.58 36.71 134

Rayong 1 14.89 4.96 100 20.5 0.54 27.38 100

LSD (P< 0.05) 6.01 2.26 - 1.55 0.05 9.75 -

CV(%) 19.66 20.85 - 4.63 4.74 17.79 -

%=Rayong 1

This promising F, from the cross of Rayong 5 x Kasetsart 50 also possessed the

same high root starch content and HI as the parents, but some clones had higher TBY.

This result was simply the segregation from the cross between two good parents, which

resulted in some better FP

Results from KU's cassava breeding program indicated that it is possible to get

a high yielding clone of cassava by a few selected crosses between two good parents.

Further progress in the Thai cassava breeding program will depend on the flow of new

selected genetic materials into hybridizing schemes.

Future Breeding Direction

Recently, Thailand is facing a severe farm labor shortage. Thus, further

improvements in cassava production depend more on mechanization. A compact root

shape to enhance the ease of machine harvesting must be considered in the future. Also,

very little attention has been paid to root HCN. Some complaints about the high HCN

content of the roots of new cassava cultivars have been received from the starch industry.

In a modern starch factory, 300-600 metric tons of fresh cassava root are crushed daily.

Consequently, vaporized HCN released in small closed-in areas may be harzardous to

workers in the factory.

62

VARIETAL MULTIPLICATION AND DISSEMINATION

Before the official release of Kasetsart 50 in 1992 and Rayong 5 in 1994, most

cassava planting stakes were exchanged freely among farmers. New improved varieties

have a high root starch content (23-24% for Kasetsart 50 and Rayong 5, as compared to

18% for Rayong 1) and a high root yield. The price of fresh roots from these two new

varieties was about 0. 10 baht per kilogram higher than from Rayong 1 . Hence, with

these two new varieties, farmers will get both a better yield and a higher price. Some

progressive farmers and factory owners multiplied and sold planting stakes of these new

varieties themselves. At the early stage of varietal release, one long stem of Kasetsart

50 might cost about 2-5 Baht. As a consequence, farmers in several locations shifted

their activities from cassava root production to cassava stake production. Several systems

of multiplication were used, such as the planting of two-node cuttings or very thin stakes,

or leaving plants in the field to cut stems twice a year instead of harvesting roots

annually. Several farmers earned large amounts of money from selling Kasetsart 50

stakes. Unfortunately, the actual amount of stakes multiplied by farmers could not be

verified.

There are two new major programs of cassava varietal multiplications. Firstly,

under the project entitled "Increase the Potential of Cassava Production," the DOAE,

mandated by MOAC, has been in charge of multiplication plots totaling 6,400 ha

annually for new varieties over a three year period (1994-1996). Participating farmers

are responsible for the multiplication of cassava stems. Stakes from these multiplication

plots have been disseminated to other farmers to set up distribution plots totaling 19,200

ha annually for three years, from 1995 to 1997. At the end of the project (1998) it is

expected that 364,800 ha of Rayong 1 will be replaced by new higher yielding cultivars.

Secondly, The Thai Tapioca Development Institute (TTDI), which is a nonprofit

foundation, was established in Sept 1993, with an initial trust fund of US$24 million

from the government. The main objectives of TTDI are: 1 . to develop high quality

cassava roots at low cost for industrial usage; 2. to develop new technology for the

manufacture of new products from cassava; and 3. to develop markets for cassava

products. Under the program of "Cost Reduction in Cassava Production", a large-scale

multiplication and distribution of new cassava cultivars has been conducted since 1995.

Details of the program of DOAE and TTDI will be discussed in the following sections.

"Increase the Potential of Cassava Production" by DOAE

According to the plan, a total of 6,400 ha of multiplication plots are planted

annually in farmers' fields by farmers under the supervision of DOAE's extension

agronomist for three years (1994-1996), resulting in planting material for a total area of

19,200 ha. New cassava cultivars are Rayong 3, Rayong 5, Rayong 60, Rayong 90 and

Kasetsart 50. RFCRC, under DOA, produces basic planting material of Rayong

cultivars, while KU produces Kasetsart 50 for DOAE to plant in the farmers' fields.

63

Participating farmers receive free planting material of the new cassava cultivars and free

15-15-15 fertilizer at the the rate of 625 kg/ha. After harvest, it is expected that five

times the original amount of cassava stakes can be obtained. Of each five stems, farmers

keep two for their own production, while the remaining three stems must be returned to

DOAE for further distribution to neighboring farmers. The distribution of new cassava

cultivars has been organized and controlled by village commitees.

In 1994, the actual multiplication area was 5,440 ha, involving 2,458 farmers

from 402 subdistricts in 134 districts in 25 provinces. Later, in 1995, the actual

multiplication area was 6,274 ha, involving 3,899 farmers from 377 subdistricts, 125

districts in 22 provinces. The total area of multiplication of each cultivar in 1994 and

1995 are shown in Table 5. For this project, KU produced for the DOAE 750,000 long

stems of Kasetsart 50 in 1994 and 1.5 million long stems in 1995.

"Cost Reduction in Cassava Production" by TTDI

In the middle of 1993 TTDI bought 260 ha of land at Huay Bong in Nakhon

Ratchasima province. This land was used to establish the "Center for Cost Reduction in

Cassava Production" . At this Center, Rayong 60, Rayong 90, Sriracha 1 , Kasetsart 50

and Rayong 1 were planted for yield comparisons in large plots. In late 1994, it was

found that Kasetsart 50 had a high root yield, high root starch content, and vigorous

stems, suitable for efficient multiplication. Therefore, the TTDI committee decided to

multiply Kasetsart 50 for distribution to farmers.

Table 5. Area planted for the multiplication of new varieties by farmers under

contract with the Department of Agricultural Extension in 1994 and 1995.

Cultivars Multiplication areas (ha)

multiplied

1994 1995

Sriracha 1 - 17

Rayong 3 599

Rayong 5 - 1 ,620

Rayong 60 2,315 690

Rayong 90 2,146 2,591

Kasetsart 50 420 1,356

Total 5,440 6,274

64

In late 1994, about 1301 farmers from 11 provinces of the Northeast received

training at the TTDI's Center on how to increase the productivity of cassava production.

Researchers from KU and RFCRC functioned as trainers. Farmers who attended the

training were eligible to receive 1,500 long stems of Kasetsart 50. This amount of

planting material is enough to plant about 0.8 ha. Farmers who received the planting

material of Kasetsart 50 must, after harvest, distribute 4,500 long stems of Kasetsart 50

to neighboring farmers. TTDI produced its own planting material of Kasetsart 50 and

bought some directly from KU. Distribution of stems of Kasetsart 50 to farmers who

attended the training in 1994 was done in the early rainy season of 1995. A total of

1,797,000 long stems of Kasetsart 50 were distributed to 1,198 farmers from 11

provinces as summarized in Table 6.

Table 6. Summary of farmers trained and new cassava cultivars distributed to

farmers by TTDI in 1995 and 1996.

1995 1996

No. of farmers trained at TTDI (persons) 1,301 7,089

No. of farmers having received stakes from TTDI 1,198 4,243

No. of farmers having obtained stakes from neighbors - 1,431

Area planted with Kasetsart 50 by TTDI-trained farmers (ha) 958 4,398

Area planted with Rayong 5 by TTDI-trained farmers (ha) - 140

In 1995/96, 7,089 farmers from 23 provinces attended the cassava training

courses. This year, the project's operational procedure is similar to that in 1994/95 with

some modification. In 1994/95, each farmer who obtained 1,500 stems of Kasetsart 50

had to distribute about 4,500 stems to neighboring farmers. The target number of

distributed stems was 5.3 million, but the actual number of stems distributed was only

about 3.0 million (56.7% of target) because of the high demand for Kasetsart 50 stakes,

and the reluctance of farmers to give the stakes to neighboring farmers. Both Kasetsart

50 and Rayong 5 are favored by farmers. Therefore, in 1995/96 TTDI required the

farmers to return stems on a 1 : 1 basis. A total of 5.9 million stems of Kasetsart 50 and

65

0.484 million stems of Rayong 5 were distributed to 4,243 farmers. Another 1,431

farmers obtained Kasetsart 50 from their neighbors who in turn had received stems from

TTDI in 1995. This resulted in a total of 8.5 million stems. The area planted to

Kasetsart 50 and Rayong 5 distributed by the TTDI project is shown in Table 6.

Varietal Adoption

Since the release of Rayong 3 in 1983, considerable efforts were made to

multiply and promote this cultivar. Klakhaeng et al. (1995) estimated that the area

planted to Rayong 3 in 1992 was 108,000 ha or about 7.3% of the total cassava growing

area. However, the yield potential of Rayong 3 is lower than that of Rayong 5, Rayong

60, Rayong 90 and Kasetsart 50. Rayong 3 is characterized by a very small plant type

compared with Rayong 1, which makes it unsuitable for growing in poor soil.

Currently, the surveyed data by DOAE revealed that in 1994 and 1995 the total

area under new cultivars was 296,254 and 387,861 ha, respectively (Table 7). In 1995,

the area under new cultivars was about 29% of the the total planting area. It was found

that the area under Rayong 3 had decreased from 135,421 ha in 1994 to only 14,953 ha

in 1995. Among the new cultivars, the area under Rayong 60 was larger than that of

Rayong 90, which was followed by that of Rayong 5 and Kasetsart 50 (Table 7). Details

of cultivar distribution among various provinces are shown in Table 8. The area planted

to new cultivars in 1995 was concentrated in some provinces, such as Nakhon

Ratchasima, Prachin Buri and Chachoengsao. Areas planted to new cultivars of some

provinces, such as Chaiyaphum, Udon Thani, Nong Khai, which are leading production

areas as well, were not as large as those of Nakhon Ratchasima, due in part to the long

distance from research stations.

It is surprising that the area under new cultivars in 1995 was already 29% of the

total cassava area, even though, the target acreage of DOAE was only 20%. The

cultivation area of the newest cultivars, Rayong 5 and Kasetsart 50, is likely to increase

dramatically in the near future, because of their high yield potential and root starch

content. Rayong 60 has also high yield potential, but the root starch content is equivalent

to that of Rayong 1, which results in a lower root price in the rainy season. Rayong 90

has high yield potential and high root starch content, but its germination rate is reduced

dramatically if stakes are stored longer than 3-4 weeks.

The area planted to new cultivars will increase rapidly if the distribution effort

is concentrated in areas where the new cultivars are presently not yet widely grown. The

rapid expansion of cultivated area of new cultivars in 1994 and 1995 may partly be due

to the farmers' own efforts. The positive impact of DOAE's and TTDI's programs on

expansion of cultivated area is likely to be materialized in the next couple of years.

66

Table 7. Areas planted to new cassava cultivars in Thailand in 1994 and 1995.

Cultivars Planted area (ha)

1994 1995

Rayong 3 135,421 14,953

Rayong 60 125,049 207,589

Rayong 90 35,461 81,049

Kasetsart 50 322 17,846

Rayong 5 NAl) 66,424

Total 296,254 387,861

:)NA = Not available

Table 8. Total planted area of cassava and area planted to new cultivars in some

leading cassava growing provinces of Thailand in 1995.

Planted area (ha)

Total area R5 R60 R90 KU50

Nakhon Ratchasima 297,679 5,467 71,095 18,777 5,640

Chaiyaphum 83,980 54 460 884 377

Chachoengsao 70,334 4,640 6,080 7,587 3,200

Prachin Buri" 67,580 7,979 16,353 5,302 4,059

Udon Thani 66,097 1,752 6,781 710 322

Nong Khai 61,369 40 174 10 16

Kamphaeng Phet 59,175 30,757 18,454 12,303 -

Kalasin 58,019 3,225 2,726 2,530 168

Khon Kaen 57,319 92 724 476 249

Chon Buri 42,439 269 838 2,908 274

Rayong 39,843 1,520 939 1,463 422

Phitsanulok 39,520 117 2,080 152 -

Total (41 provinces)2) 1,322,859 66,423 207,588 81,049 17,846

"including Srakaew province.

^in each column the figure reflects the total cassava cultivation area of 41 provinces.

67

An evaluation of the root yield of Kasetsart 50 was conducted by TTDI. A

survey of yield performance from 26 farmers in 8 provinces who had received Kasetsart

50 from TTDI in 1995 was conducted during April 1996. An average yield of 26.4 t/ha

with 27% root starch content was obtained from Kasetsart 50, as shown in Table 9. The

result is very satisfactory in comparison to the nation average yield of around 14 t/ha.

With this result, theTTDI committee approved further multiplication of new cultivars in

1997 for the third year.

Table 9. Yield of Kasetsart 50 in farmers' fields, as indicated by a survey of 26

TTDI-trained farmers in 1996.

Provinces No. of farms Germination Root Root starch

surveyed (%) yield

(t/ha)

content

(%)

Chaiyaphum 2 87 23.6 23

Nakhon Ratchasima 6 70 25.5 25

Buri Ram 4 78 32.9 28

Khon Kaen 5 78 29.2 28

Kalasin 2 70 21.3 27

Sakon Nakhon 4 83 29.3 27

Nongbua Lampoo 2 87 24.8 27

Udon Thani 1 81 18.5 28

Average 77 26.4 27

68

REFERENCES

Kawano, K. 1988. CIAT cassava germplasm development in Asia - Cooperation with

national programs. In: R.H. Howeler and K. Kawano (Eds.). Cassava Breeding and

Agronomy Research in Asia. Proc. of a Regional Workshop, held in Rayong,

Thailand. Oct 26-28, 1987. pp. 117-126.

Kawano, K., S. Sarakam, A. Limsila, A. Tongglum and D. Supraharn. 1990. Cassava

cultivar evolution viewed through harvest index and biomass production. In: R.H.

Howeler (Ed.). Proc. 8th Symp. Int. Soc. Trop. Root Crops, held in Bangkok,

Thailand. Oct 30-Nov 5, 1988. pp. 202-211.

Klakhaeng, K., C. Boonmark and C. Chainuvat. 1995. Cassava extension organization

and activities in Thailand. In: R.H. Howeler (Ed.). Cassava Breeding, Agronomy

Research and Technology Transfer in Asia. Proc. 4th Regional Workshop, held in

Trivandrum, India. Nov 2-6, 1993. pp. 135-146.

Limsila, A., C. Rojanaridpiched, C. Tiraporn, S. Sinthuprama and K. Kawano. 1992.

In: R.H. Howeler (Ed.). Cassava Breeding, Agronomy and Utilization Research in

Asia. Proc. 3rd Regional Workshop, held in Malang, Indonesia. Oct 22-27, 1990.

pp. 34-43.

Rojanaridpiched, C, A. Limsila, D. Supraharn, O. Boonseng, P. Poolsanguan, C.

Tiraporn, and K. Kawano. 1995. Recent progress in cassava varietal improvement in

Thailand. In: R.H. Howeler (Ed.). Cassava Breeding, Agronomy Research and

Technology Transfer in Asia. Proc. 4th Regional Workshop, held in Trivandrum,

Kerala, India. Nov 2-6, 1993. pp. 124-134.

Tan, S.L. 1987. Selection for yield potential in cassava. In: C.H. Hershey (Ed.). Cassava

Breeding: A Multidisciplinary Review. Proc. of a Workshop, held in the Philippines.

March 4-7, 1985. pp. 67-88.

69

CASSAVA VARIETAL IMPROVEMENT IN VIETNAM

Tran Ngoc Ngoan1, Tran Ngoc Quyeri2, Trinh Phuong Loan3 and Kazuo Kawano*

ABSTRACT

In recent years (1990-1995) the cassava area in Vietnam has remained stable, or has

increased slightly in the south due to the new demand for cassava roots used for starch processing.

Therefore, our cassava breeding program, in collaboration with CIAT, has put a high priority on

developing new varieties with high yield potential and high dry matter and starch content in the

roots.

Due to the particular agro-climatic conditions in Vietnam the country can be divided into

two large regions. The south is characterized by a tropical climate, while the north has a sub

tropical climate. So, new varieties adapted to these specific environments are also needed.

Out of the 29 promising clones introduced from the Thai-CIAT program in 1989 and

1990, two best selections, KM60 and KM94, have been giving 17 to 112% higher dry root yields

and 10 to 103% higher fresh root yields compared to the local cultivars at research stations, and

30 to 47% higher fresh root yields in cassava production zones. Both KM60 and KM94 were

officially released early in 1995. They were grown over 7000 ha in 1995 and are expected to be

planted in about 30,000 ha in the 1996/97 crop year. The additional economic benefit resulting

from adoption of the new cultivars was estimated to have reached 0.95 million US dollars in 1995

and is expected to reach 5 million US dollars in 1996.

Some promising clones may be adapted to specific locations. Clone SM937-26 gave very

good yields at Lam Dong and Khanh Hoa provinces, CMR29-60-15 and SMI 157-3 in Ha Tay

province, while SMI 157-3 and SM981-3 were best in Bac Thai province. These clones are now

included in Regional Trials and in the On-farm Evaluation Network in 1996.

Follow-up selection of genotypes adapted to our cassava production conditions started in

1990. Some promising clones, like OMR33-17-15 in the south and CM4955-7 in the north, are

being evaluated on farmer's fields this year. They are both the result of intensive selection by

HARC and the Agro-forestry College in Bac Thai from hybrid seeds provided by CIAT/Colombia

and the Thai-CIAT program. Although the rate of selection with CIAT/Colombia materials is not

quite as high as those from the Thai-CIAT program, the greater genetic diversity of this material

is playing an important role in cassava breeding and genetic improvement in Vietnam. Results

from our current selection will identify new high-yielding cultivars and bring economic benefits

for growers and processors; they may also open up new export opportunities by greater product

competitiveness in international markets.

INTRODUCTION

During recent years (1990-1995) the cassava area in Vietnam has been stable or

has slightly increased in the south by the setting up of new starch and monosodium

glutamate factories. The demand for cassava fresh roots as raw material for these

factories ranges from 270,000 to 600,000 t/year. Traditional rural processing of cassava

1 Agro-forestry College of Thai Nguyen University, Thai Nguyen, Bac Thai, Vietnam.

2 Hung Loc Agric. Research Center (HARC) of IAS, Thong Nhat - Dong Nai, Vietnam.

3 Potato and Vegetable Research Center (PVRC), Thanh Tri Van Dien, Hanoi, Vietnam.

4 CIAT Asian Cassava Program, Dept. Agriculture, Bangkok, Thailand.

70

fresh roots into starch and maltose around Ho Chi Minn city and Hanoi consumed about

395,077 ton fresh roots in 1992, and this is expected to reach 898,740 ton fresh roots by

the year 2000. Cassava is thus becoming an industrial crop in some parts of the country.

Therefore, the cassava breeding program in Vietnam, in cooperation with CIAT,

has put high priority in developing new varieties that have high yield potential and high

root dry matter content, which is suitable as raw material for the processing industry.

Breeding materials, both in the form of stem cuttings from the Thai-CIAT program and

hybrid seeds from CIAT/Colombia and the Thai-CIAT program have been introduced and

evaluated in order to select the most suitable genotypes under our cassava production

conditions.

Soils and Agro-Climate

Vietnam is located between latitudes 8.5 and 23.5° N and longitudes 102 and 1 10°

E. The country has been divided into seven Agro-ecological zones. In general, the

northern part is characterized by a subtropical climate with low winter (15°C) and high

summer (29°C) temperatures. Most rain falls during the summer months of May to Sept.

In the south, the climate is tropical with relatively little fluctuation in monthly

temperatures, which vary from 25 to 29°C. The rainy season is about one month delayed

compared with the north, but total rainfall is similar (Nguyen Huu Hy et al., 1995).

The soils of Vietnam are closely associated with its topography. It was estimated

that in Vietnam about 66% of cassava is grown on Ultisols, 17% on Inceptisols, 7% on

Oxisols, 4% on Alfisols, 2% on Entisols and 3% on Vertisols (Howeler, 1992). The soil

pH generally varies from 4.5 to 6.0. Therefore, one important breeding objective is to

develop new varieties adapted to specific environments.

Breeding Objectives and Materials

Cassava breeding in Vietnam is mainly conducted by three institutions under the

coordination of the National Root Crops Program, i.e. Hung Loc Agricultural Research

Center in the south, the Agro-Forestry College of Thai Nguyen Univ. in Bac Thai and

the Potato and Vegetable Research Center in Hanoi.

Breeding materials have been introduced from CIAT since 1989 and upto 1995

these consist of:

-29 promising clones from the Thai-CIAT program

-Hybrid seeds from CIAT/Colombia

-Hybrid seeds from the Thai-CIAT program

The general cassava breeding objective in Vietnam is to develop promising clones

with the following characteristics:

-High yield potential and high dry matter and starch contents in the roots

-Sweet varieties for specific end-uses

71

-High harvest index (HI)

-Early harvestability (8-10 months)

-Adaptation to acid infertile soils and to low levels of inputs

-Good plant type for association with other crops

-Specific adaptation to a given region

Research methodologies as well as on-farm evaluations have followed the CIAT

breeding scheme.

ACHIEVEMENTS

Evaluation of Promising Clones Introduced from the Thai-CIAT Program in 1989

Success of Two New Recommended Varieties, KM60 and KM94

After the introduction in 1989 of 29 promising clones from the Thai-CIAT

program in the form of stem cuttings, a series of intensive evaluations have been

conducted by the cassava breeding network throughout the country. From this, two

varieties, Rayong 60 and Kasetsart 50, were selected and renamed as KM60 and KM94,

respectively. These have been released as new varieties and have been widely adopted

by farmers. In the south, these varieties have been giving from 66 to 103% higher yields

than the improved local cultivar, HL23, in terms of fresh roots, and from 75 to 112%

in terms of dry root yield at research stations; and from 30 to 38% higher fresh root

yields in on-farm production trials (Tables 1 and 2). In the north, the yields of KM60

and KM94 at research station trials were only 10-13% higher than those of the local

cultivar, Vinh Phu, but in on-farm production their fresh root yields were 30-47% higher

than those of Vinh Phu (Tables 1 and 2). The dry matter contents of these varieties are

also 4-8% higher than those of the local cultivars.

72

Table 1. Comparison of average yield parameters of KM60 and KM94 with those

of local varieties at Research Stations in North and South Vietnam from

1990 to 1995.

Clones Fresh root % of Dry matter % of Dry root % of

yield control content control yield control

(t/ha) (%) (t/ha)

NORTH

KM94 24.9 110 40.0 108 9.85 117

KM60 25.6 113 38.5 104 9.96 119

Vinh Phu 22.6 100 37.0 100 8.36 100

SOUTH

KM94 36.60 203 38.3 104 14.0 212

KM60 29.95 166 38.7 106 11.6 175

HL23 18.00 100 36.5 100 6.6 100

Table 2. Comparison of average fresh root yields of KM60 and KM94 with those of

local varieties in On-Farm Production in North and South Vietnam from

1992 to 1995.

Clones South North

t/ha % of control t/ha % of control

KM94" 35.0 138 25.6 147

KM60 33.0 130 22.6 130

Local cultivars 25.2 100 - -

Vinh Phu - - 17.3 100

"Data for 1995 only

73

Both KM60 and KM94 were officially released early in 1995 and were quickly

disseminated in cassava production areas by the cassava technology transfer network. It

was estimated that about 7,000 ha were grown with these two varieties in 1995 and that

the area planted exceeded 30,000 ha in 1996.

The adoption of KM60 and KM94 as new high-yielding cultivars partly satistifies

the increasing demand for good raw materials for the starch processing industry. It is

also bringing additional economic benefits to farmers, which was estimated to have

reached 0.95 million US dollars in 1995 (Kawano, 1995).

Varietal Selection for Adaptation to Specific Regions

One of the most important characteristics of KM60 and KM94 is that they are

adapted to a wide range of agro-ecological conditions as well as to variable farmer's

practices; hence, in this case there is little interaction between genotype and environment.

But for future genotypes it may be necessary to exploit more fully the potential of certain

clones for specific regions.

Results of yield trials conducted at Hung Loc Research Center in south Vietnam

have shown that SM937-26 gave very good yields at Lam Dong and Khanh Hoa

provinces (Table 3), while CMR29-60-15 and SMI 157-3 were good in Ha Tay (Table

4), and SM981-3 and SMI 157-3 were the highest yielders in Bac Thai province (Table

5). These clones are now included in the Regional Trials and On-farm Evaluation

Network in 1996.

Table 3. Results of Regional Yield Trials conducted by Hung Loc Agric. Research

Center in Central and South Vietnam in 1994.

Clones Fresh root yield at various locations (t/ha)

Average

Thua Quang Quang Khanh Binh Dac Lam yield

Thien Nam Ngai Hoa Thuan Lac Dong (t/ha)

KM94 42.1 34.5 38.8 52.5 21.5 27.3 26.5 34.7

SM937-26 33.8 27.7 26.2 56.4 18.8 19.6 25.0 29.6

CMR937-14 - - - 42.6 15.5 - 22.2 26.7

KM60 40.4 26.8 34.8 64.4 19.5 25.2 24.9 33.7

Local check" 37.5 21.5 16.9 57.6 19.3 13.5 19.9 26.6

''Local checks: H34, Nam Thuc and Gon

74

First Promising Clones Selected from Hybrid Seeds

The introduction of hybrid seeds of selected crosses from CIAT started in 1990.

Recurrent evaluation from this seed is an opportunity to select those genotypes most

adapted to our specific cassava production conditions. During five years of intensive

selection from the seeds introduced in 1990 and 1991, OMR33-17-15 gave very

promising results in the south (Table 6) and CM4955-7 in the north (Table 7).

Table 4. Results of an Advanced Yield Trial conducted at the Potato and Vegetable

Research Center in Hanoi in 1995.

Clones Fresh root Root dry Dry root Harvest

yield matter content yield index

(t/ha) (%) (t/ha)

KM94 26.83 40.1 10.76 0.64

KM60 22.67 38.4 8.71 0.60

CMR29-60-15 24.83 39.1 9.71 0.61

SMI 157-3* 23.00 37.4 8.60 0.59

CMR25-33-105 21.33 37.7 8.04 0.66

SM981-3* 18.50 38.8 7.18 0.55

Vinh Phu (Local) 19.50 38.6 7.53 0.58

Table 5. Results of an Advanced Yield Trial conducted at Agro-forestry College in

Bac Thai in 1995.

Clones Fresh root Total biomass Harvest Root dry Dry root

yield yield index matter content yield

(t/ha) (t/ha) (%) (t/ha)

Vinh Phu 17.1 26.5 0.64 38.4 6.5

KM60 20.5 30.5 0.67 41.4 8.5

SMI 157-3" 28.0 45.3 0.62 41.6 11.6

SM981-3" 24.0 36.0 0.66 41.6 10.0

OMR25-33-105 19.8 27.0 0.73 41.6 8.2

CMR29-60-15 20.0 32.0 0.62 43.2 8.6

SM937-8" 22.6 35.9 0.63 40.0 8.9

"Clones have been selected from hybrid seeds at Hung Loc Agric. Research Center

75

Table 6. Fresh root yield of OMR33-17-15 in comparison with those of KM94,

KM60 and local cultivars at some locations in South Vietnam in 1994.

Fresh rool: yield at various locations (t/ha)

Average

Clones Xuan Tra Long Tay Ho Chi yield

Thanh Co Thanh Ninh Minn (t/ha)

OMR33-17-15 27.1 35.7 41,0 29.3 49.5 40.5

KM94 27.8 42.5 46,0 41.7 50.4 41.7

KM60 23.1 37.1 - 30.6 - 30.3

Local cultivars 12.7 - - 26.1 21.1 19.9

Source: Tran Ngoc Quyen, 1994

Observation of Yield Potential of Materials Introduced from CIAT/Colombia and

the Thai-CIAT Program

It is obvious that cross parents have not been selected only for our ecosystem.

Some progenies may show good performance, while others may not be quite so good in

the new environment. Therefore, it is also important to estimate the yield potential of

different materials under our own conditions to get feedback for future selections. From

hybrid seeds introduced in 1993, we have seen that the selection rate in F, seedlings

derived from hybrid seeds from CIAT/Colombia was lower than from the Thai-CIAT

materials, i.e 18.5 and 21.0%, respectively. Especially in Single Row Trials, the

selection rate of CIAT/Colombia materials was much lower than that of Thai-CIAT

materials (14 and 40%, respectively) (Table 8). This observation was confirmed in the

Preliminary Yield Trial conducted at the Agro-forestry College in Bac Thai in 1995

(Table 9). The best clones that have been selected for the Replicated Yield Trial in 1996

indicate that Thai-CIAT materials seem to be better than CIAT/Colombia materials for

direct selection of promising clones that can be recommended for cassava production.

It is too early to draw any conclusion, because the success of a breeding program

depends not only on the skill of the breeders but also on the breeding materials. So,

having good parental materials with wide genetic variability will give us a good chance

to select the most suitable genotypes for both direct-use and for the future breeding

program.

76

Table 7. Results of an Advanced Yield Trial conducted at Agro-forestry College in

Bac Thai in 1994.

Clones" Fresh root Total biomass Harvest Root dry Dry root

yield yield index matter content yield

(t/ha) (t/ha) (%) (t/ha)

Vinh Phu(check) 15.6 25.8 0.60 38.4 6.0

KM60(check) 24.5 40.0 0.61 41.5 10.1

CM4955-7 30.0 48.5 0.62 41.5 12.4

SM 1035-1 21.0 37.6 0.55 39.8 8.3

CM7889-10 18.7 29.7 0.63 38.9 7.2

CM7909-2 18.5 33.7 0.55 36.3 6.7

CM7889-2 15.8 28.3 0.56 41.5 6.5

SM 1200-6 16.2 24.7 0.65 38.3 6.2

SM1079-1 14.7 30.3 0.48 40.4 5.9

"Clones had been selected from hybrid seeds introduced in 1991

Table 8. Results of an evaluation of the selection rate of materials introduced from

CIAT/Colombia and the Thai-CIAT program in Fl Seedling and Single

Row Trials conducted at Agro-forestry College in Bac Thai in 1993 and

1994.

Stage of evaluation CIAT/ Thai-CIAT Vinh Phu KM60

Fl Seedling Trial 5

Colombia (check) (check)

-Total seeds 3000 1004 - -

-No of clones harvested 384 262 - -

-No of clones selected for next step 71 55 - -

-Selection rate(%) 18.5 21.0 - -

Single Row Trials

-Mean fresh root weight(t/ha) 16.3 22.8 17.6 23.5

-Mean total plant weight(t/ha) 32.6 39.0 31.7 37.5

-Mean harvest index 0.50 0.58 0.55 0.62

-Mean RDMC" 37.3 41.6 39.4 42.3

-No of clones selected for next step 10.0 21.0 - -

-Selection rate(%) 14.0 40.0 - -

l)RDMC= Root dry matter content

77

Table 9. Average yield parameters of clones selected from seeds introduced from

CIAT/Colombia and the Thai-CIAT program in a Preliminary Yield

Trial conducted at Agro-forestry College in Bac Thai in 1995.

Mean traits CIAT/ Thai-CIAT Vinh Phu KM60

All entries mean

Colombia (check) (check)

-Fresh root yield(t/ha) 23.9 25.3 26.4 30.0

-Biomass yield(t/ha) 45.6 45.6 45.2 46.2

-Harvest index 0.52 0.55 0.58 0.64

-RDMC"(%) 38.5 38.8 38.8 39.2

-Starch content(%) 27.3 27.6 27.4 28.1

Clones selected for RYT"

-Fresh root yield(t/ha) 27.3 32.0 - -

-Biomass yield(t/ha) 47.1 52.2 - -

-Harvest index 0.58 0.61 - -

-RDMC(%) 37.2 39.6 - -

-Starch content(%) 25.6 28.3 - -

"RDMC = Root dry matter content; RYT = Replicated Yield Trial

CONCLUSIONS

During the past five years much progress has been made in cassava varietal

improvement in Vietnam. Figure 1, 2 and 3 show that in all three institutions involved

in cassava breeding in Vietnam, the fresh yield of the breeding population increased

markedly compared to that of the control varieties, while the root dry matter content also

increased to 5-10% above that of the control varieties. Two high-yielding varieties,

KM60 and KM94, that are well adapted to our conditions have been officially released

and have brought additional economic benifits for farmers.

Breeding materials introduced both from CIAT/Colombia and from the Thai-

CIAT program have played a significant role in cassava varietal improvement in

Vietnam. At present, several promising clones selected from these materials, which have

some outstanding characteristics, may in the future supply the raw material for processing

factories, for animal feed and for other specific end-uses through further breeding and

the strengthening of the technology transfer network.

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REFERENCES

Dang Thanh Ha, Le Cong Tru and G. Henry. 1996. Analysis of the current and future cassava

starch market in Vietnam. In: R.H. Howeler (Ed.). Cassava Production, Processing and

Marketing in Vietnam. Proc. of a Workshop held in Hanoi, Vietnam. Oct 29-31, 1992.

pp. 159-172.

Henry, C, Le Cong Tru and V. Gottret. 1996. Vietnamese cassava constraints and opportunities:

The bottom line. In: R.H. Howeler (Ed.). Cassava. Production, Processing and Marketing in

Vietnam. Proc. of a Workshop held in Hanoi, Vietnam. Oct 29-31, 1992. pp.203-220.

Howeler, R.H. 1992. Agronomy research in the Asian cassava network. An overview 1987-1990.

In: R.H. Howeler (Ed.). Cassava Breeding, Agronomy and Utilization Research in Asia. Proc.

3rd Regional Workshop, held in Malang, Indonesia. Oct 22-27, 1990. pp.260-285.

Kawano, K. 1995. Cassava varietal improvement in the developing economy of Vietnam. Paper

presented at the National Food Crop Program Meeting, held by MAFI in Hanoi. Sept, 1995.

Nguyen Huu Hy, Tran Dai Nghia and Pham Van Bien. 1995. Recent progress in cassava

agronomy research in Vietnam. In: R.H. Howeler (Ed.). Cassava Breeding, Agronomy

Research and Technology Transfer in Asia. Proc. 4th Regional Workshop, held in Trivandrum,

Kerala, India. Nov 2-6, 1993. pp.237-252.

Nguyen Van Thanh. 1996. Cassava in Vietnam: An overview. In: R.H. Howeler (Ed.). Cassava

Production, Processing and Marketing in Vietnam. Proc. of a Workshop held in Hanoi,

Vietnam. Oct 29-31, 1992. pp.12-33.

Tran Ngoc Quyen, Vo Van Tuan, K. Kawano and Hoang Kim. 1997. Cassava germplasm and

results of cassava improvements in South Vietnam. In: Hoang Kim and Nguyen Dang Mai

(Eds.). New Progress in Cassava Research and Extension in Vietnam. Proc. Cassava

Workshop held at Hung Loc Agric. Research Center. Dongnai, Vietnam. March 5-7, 1996.

pp. 24-34. (in Vietnamese)

82

CASSAVA VARIETAL DISSEMINATION IN VIETNAM

Hoang Kim1, Tran Ngoc Quyen1., Pham Van Bien2 and Kazuo Kawand*

ABSTRACT

Before 1985, Gon, H34 and Xanh Vinh Phu were the most popular cassava varieties in

Vietnam. From 1986 to 1993, HL20, HL23 and HL24 were selected from the local variety

collection by Hung Loc Agricultural Research Center (HARC) and were grown extensively in

South Vietnam with annual areas of about 70,000 to 80,000 ha planted to these varieties.

More recently (1993-1996) the Vietnam Root Crops Program in cooperation with CIAT,

selected and recommended two new cassava varieties, KM60 (Rayong 60) and KM94 (MKUC 28-

77-3); these were recognized and released for production by the Ministry of Agriculture and Rural

Development (MARD). The two varieties are now widely grown in an area of about 15,000 ha

in 1996.

The report presents the linkage between cassava research and extension activities in

Vietnam. Experiences and methods of cassava varietal dissemination include ten mutual link-up

activities (ten Ts). The most important one was the establishment of the Vietnam Cassava

Research and Extension Network (including advanced cassava farmers, researchers, extensionists,

managers of cassava research and development projects, cassava trade and processing companies),

and the establishment of on-farm research and demonstration fields (Farmer Participatory Research

- FPR).

The Vietnam Cassava Research and Extension Network obtained good results during the

period of 1993-1995. Advanced fanners who obtained high yields and high profits due to the

growing of improved cassava varieties, became attractive models for other cassava growers,

resulting in the expansion of new varieties. In Tay Ninh province, for example, in 1990 the

cassava growing area was 3,350 ha, with an average yield of 10.8 t/ha and a total production of

36,200 tons. With the planting of new high-yielding varieties and new cultivation techniques, in

1995 the cassava growing areas had increased to 18,870 ha with an averaged yield of 20.5 t/ha

and a total production of 386,900 tons.

Six essential conditions for the successful cassava varietal dissemination in Vietnam

include: Materials, Markets, Management, Method, Manpower and Money (six Ms). However,

other problems should be taken into account: Crop competition (especially between cassava and

sugarcane); soil fertility degradation and erosion; and decreasing varietal diversity.

INTRODUCTION

Cassava in one of the main crops in Vietnam (Table 1). It plays an important

role in the strategy of national food security. It is also a main source of raw material for

starch and animal feed factories. In 1995, the total cassava area reached 277,500 ha with

an average yield of 8.0 t/ha and a total production of 2,21 1,700 tons (General Statistical

Office, 1996).

1 Hung Loc Agric. Research Center (HARC) of IAS, Thong Nhat, Dong Nai, Vietnam.

2 Institute of Agricultural Sciences of South Vietnam (IAS), Ho Chi Minn city, Vietnam.

3 CIAT Asian Cassava Regional Program, Dept. Agriculture, Bangkok, Thailand.

83

Table 1. Area, yield and production of principle crops in Vietnam in 1995.

Crop Area Yield Production

Food crops

COOOha) (t/ha) COOOt)

Rice 6,765.6 3.69 24,962.8

Maize 556.8 2.13 1,484.2

Sweet potato 304.6 5.53 1,685.8

Cassava 277.5 7.97 2,221.7

Vegetables 328.2 12.62 4,145.6

Beans 187.5 0.68 126.7

Annual industrial crops

Groundnuts 259.9 1.28 334.4

Soybean 121.1 1.03 125.5

Sugarcane 224.8 47.60 10,711.2

Tobacco (leaves) 27.0 1.00 27.0

Mulberry 21.8 6.84 148.9

Cotton 14.6 0.71 10.0

Rushes 9.0 6.49 5.9

Jute 4.2 2.27 9.5

Perennial industrial crops

Rubber 278.4 0.84" 122.7

Coffee (beans) 186.4 2.18" 218.1

Tea (dry) 66.7 3.41" 180.9

Cashew nut" 250.0 0.83" 100.0

Fruits2) 310.0 - -

Pepper21 7.0 1.28 9.0

" The harvested areas of rubber, coffee, tea and cashew nut in 1995 are:

146,900, 99,900, 53,000 and 120,000 ha, respectively.

Source: General Statistical Office, 1996

Cassava areas and production in Vietnam have flucated markedly during the period

from 1976 to 1995 (Figure 1). The biggest cassava area was 461,400 ha with a total

production of 3,422,000 tons in 1979. Cassava root yield increased from 7.5 t/ha in

1980 to 8.0 t/ha in 1995 (Nguyen Van Thang, 1996).

Before 1985, the most popular cassava varieties grown in Vietnam were Gon, H34

and Xanh Vinh Phu. During the period of 1986-1993 (Table 2), three cassava varieties,

HL20, HL23 and HL24, were selected from local cassava collections and released by the

Hung Loc Agricultural Research Center (HARC). They were grown annually on about

70,000 ha in South Vietnam (Tran Ngoc Ngoan et al., 1995).

84

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85

Table 2. Cultivar distribution in representative cassava growing regions in Vietnam

(% in each region).

Region

Cultivar Northern Red North South Central South

(local name) Mountain River Central Central Highlands eastern

Region Delta Coast Coast Region

Mi Xanh(Vinh Phu) 51.2 4.2 9.8 0 0 0

Mi Trang 16.0 92.7 27.5 0 0 0

Chuoi 12.9 0 0 0 0 0

Man 0 2.1 6.9 0 0 0

Du 1.4 0 2.0 0 0 0

HaBac 1.1 0 2.5 0 0 0

Gon(Mi Do) 7.7 1.0 11.8 6.6 2.0 12.4

H34 0 0 9.6 28.2 77.0 6.8

HL20 0 0 0 0 0 33.6

HL23 0 0 0 36.3 0 8.2

HL24 0 0 0 0.7 21.0 30.9

Others 9.8 0 30.0 28.2 0 8.1

Source: Tran Ngoc Ngoan el al.,1995

The Vietnam Root Crops Program, with strong supports from OAT, has made

considerable progress since 1988. During the period of 1993-1995, two new cassava

varieties, KM60 (Rayong 60) and KM94 (MKUC28-77-3), were recommended and

allowed to be released for production by the Ministry of Agriculture and Rural

Development (MARD). The two varieties are now widely grown in an area of about

15,000 ha in 1996.

Advanced farmers who obtained good yields and high profits from growing

improved cassava varieties became attractive models for other cassava growers, resulting

in the expansion of new varieties. In Tay Ninh province, for examples, the total cassava

area in 1990 was 3,350 ha with an average yield of 10.8 t/ha and total production of

36,200 tons. However, with the planting of new high-yielding varieties and applying

new cultivation techniques, the cassava area increased to 18,870 ha with an average yield

of 20.5 t/ha and a total production of 386,900 tons in 1995 (General Statistical Office,

1996).

This report presents methods and experiences in cassava varietal dissemination

in Vietnam. The report also introduces the initial results and discusses the essential

conditions required for success in cassava varietal dissemination, and outlines new

86

problems and challenges in cassava production in Vietnam.

METHODS OF CASSAVA VARIETAL DISSEMINATION IN VIETNAM:

A CASE STUDY OF HARC.

1. Establishment or National Cassava Research and Extension Network

The chart shown in Figure 2, indicates the coordination between cassava research

and extension activities. It was considered essential to build up a National Cassava

Research and Extension Network, which includes advanced cassava farmers, researchers,

extensionists, managers of cassava research and development projects, as well as cassava

trade and processing companies. The network was established in 1991 and workshops

have been organized annually at HARC. The objectives, responsibilities, subjects and

methods of operation were further developed and adapted to Vietnamese production

conditions in the course of the years (Hoang Kim et al., 1995).

2. Establishment of Demonstration Fields and On-farm Research (OFR)

On-farm research and the transfer of technologies were particularly emphasized:

HARC focussed mainly on three related research areas, i.e. breeding, cultivation

techniques and the transfer of technologies (Hoang Kim et al., 1995). Methodologies to

study cropping systems, developed by IRRI, (Zandstra et al., 1981; Carangal, 1990) and

agricultural ecology systems analysis (Conway, 1986) were used in cassava research and

development programs.

Cassava breeding lines were evaluated first in Preliminary Yield Trials (PYT),

which are non-replicated with a plot area of 12-36 m2. The selected accessions then were

evaluated in Standard Yield Trials (SYT) and Regional Yield Trials (RYT) using a

completely randomized block design (CRBD) with a plot area of 30-50 m2 and 3-4

replications.

The most promising clones were demonstrated on farmers' fields with 4-5

varieties (including two local popular varieties) per household. Each variety was grown

in 10-30 m2 without replication. Two to four promising varieties (including one local

variety) were then selected and evaluated in pre-production plots of 1000 m2 per variety.

A field day was organized at harvesting time.

88

3. Ten Mutual Link-up Extension Activities (ten Ts)

The extension methodology used by the Institute of Agricultural Science of South

Vietnam (IAS) can be summarized by the following ten words starting with the letter T

(in Vietnamese):

1 . Thu nghiem Trials

2. Trinh dien Demonstrations

3. Tap huan Training

4. Trao doi Exchange

5. Tham vieng Farmer tours

6. Tham quan hoi nghi dau bo Farmer field day

7. Thong tin tuyen truyen Information, propaganda

8. Thi dua Competition

9. Tong ket khen thuong Recognition, praise and reward

10. Thanh lap mang luoi Establish good farmers' network

nguoi nong dan gioi

RESULTS AND DISCUSSION

a. Results

HARC's cassava germplasm includes 71 local cultivars and 26 cultivars and

promising clones introduced from CIAT, as well as 26,652 hybrid seeds introduced from

CIAT/Colombia and from the Thai-CIAT program. KM60 was the highest yielding

variety in all RYT and On-farm Trials from 1990 to 1992 (Table 3). This variety is

preferred because of its higher starch yield as compared to the local ones. It is also

tolerant to drought and has a straight stem and little branching.

KM94 has been the best variety in all SYT at HARC from 1991 to 1993 (Table

4). KM94 was also evaluated in RYT in 25 locations in several provinces in 1994. It

was selected for production because of its consistent high yield (Table 5 and 6). KM60

and KM94 are now expanding rapidly in production. In the latter part of 1996 the two

varieties are being planted in about 15,000 ha (Table 7), mainly concentrated in Dong

Nai, Tay Ninh, Song Be, An Giang, Quang Ngai, Gia Lai, Lam Dong, Ba Ria-Vung

Tau, Dac Lac, Binh Thuan and Binh Dinh provinces.

A comparision in terms of economic returns between KM60 and HL20 in Dong

Nai (Table 8) shows that KM60 produced a profit of 7.71 million dong/ha, while HL20

only gave 4.19 million dong/ha (Ao Van Thinh, 1996).

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An outstanding example is Tay Ninh, where the new high-yielding cassava

varieties are rapidly replacing the local low-yielding clones. Before 1990, Gon, H34 and

Binh Duong varieties comprised 100% of production. In 1995, however, the new

varieties covered 80-90%, while the newest clones, i.e. KM60, KM94, SM937-26, and

KM95, covered about 20% of the total cassava area of Tay Ninh. According to Table

9, the averaged yield in 1995 was 20.5 t/ha in 18,850 ha, resulting in a total production

of 386,900 tons, as compared to an average yield in 1990 of 10.8 t/ha, a planting area

of 3,350 ha and production of 36,200 tons (Tran Vien Thong, 1996).

An economic analysis shows that in Tay Ninh the planting of KM60 could give

a net income of 4.46 million dong/ha with an average yield of 20 t/ha in 1995 (Table

10).

Table 11 shows the inputs and economic benefits obtained by three advanced

cassava farmers who planted the new variety KM60. Private companies that participated

in the cassava R&D system also promoted greatly the varietal dissemination and the

change in cropping systems. In 1995, KM60 and KM94 were released as national

varieties.

Table 9. Cassava growing area, yield and production in Tay Ninh province

from 1990 to 1995.

Year Area(ha) Yield (t/ha) Production (t)

1990 3,355 10.8 36,210

1991 7,366 11.5 85,142

1992 7,173 11.7 83,652

1993 9,337 13.7 129,624

1994 15,846 18.7 196,598

1995 18,849 20.5 386,904

Source: General Statistical Office, 1996.

Tran Vien Thong, 1996.

96

Table 10. Cost and return analysis per hectare for a new cassava production

scheme using cultivar KM60 in Tay Ninh province in 1995,

assuming a yield of 20 t/ha fresh roots.

Unit Amount Unit price

COOOd)

Total price

COOOd)

1.Total cost: 3,937

Plowing buffalo-day 3 140 420

Other land preparation buffalo-day 1 150 150

Planting man-day 12 12 144

Weeding man-day 10 12 120

Harvesting man-day 30 12 360

Transportation pick-up 4 200 800

Planting stakes bundle 50 10 500

Chemical 72

Herbicide liter 2 170 340

Urea bag of 50 kg 1 148 148

Ammounium sulfate bag of 50 kg 3 75 225

Single superphosphate bag of 50 kg 6 48 288

Potassium chloride bag of 50 kg 3 90 270

Farm yard manure t 2 50 100

2.Gross income: 8,400

Root harvest t 20 300 6,000

Planting stakes bundle <too 6 2,400

3.Net income: 4,463

1US$ = 1 1,000 dong

Source: Agriculture and Forestry Service of Tay Ninh province.

97

Table 11: Cost of production, gross and net income of three advanced cassava

farmers in South Vietnam in 1995/96.

Item

Name of farmer

N.H. Cuong Ho Sau T.Q. Thanh

(Dong Nai) (Ding Nai) (Tay Ninh)

Variety planted KM 60 KM 60 KM 60

Farm size (ha) small medium large

Yield (t/ha) 25 30 25

Price fresh roots (d/kg) 500 350 570

Total production costs('000d/ha) 6,440 4,210 3,930

Gross income('000d/ha) 12,500 10,500 14,250

Net income('000d/ha) 6,060 6,290 10,220

Source: Nguyen Hung Cuong, 1997

Ho Sau, 1997

Tong Quoc Thanh, 1997

b. Six essential conditions for the successful cassava varietal dissemination

To ensure that the cassava varietal dissemination is successful, the following

factors should be of mayor concern: Materials, Markets, Management, Method,

Manpower and Money.

Materials: The Vietnam Root Crops Program maintains a collection of promising

cassava germplasm, consisting of both local varieties and clones introduced from CIAT;

this constitutes a very important genetic resource for the country and guarantees future

progress in cassava varietal improvement (Figure 4).

Markets: Cassava utilization for human consumption decreased. However,

cassava demand for industrial and animal feed processing increased greatly in Vietnam.

From 1990 up to 1996, the cassava market has been expanding. Many cassava

processing factories were established and are now operating, thus greatly stimulating

cassava production and development (Figure 5).

Management: Changes in goverment policy and economic reform created

favorable conditions for agricultural development and stimulated the use of new varieties

and the application of advanced cultivation techniques in cassava production. The

Cassava R&D Network also plays an essential role in the evaluation and dissemination

98

of new varieties (Huang Kim et al., 1995).

Method: It is essential to plant demonstration fields and on-farm trials and to

conduct Farmer Participatory Research (FPR) to enhance varietal dissemination. Varietal

improvement should be combined with studies of cultivation techniques in certain

cropping systems.

Manpower: Vietnamese farmers, especially advanced farmers, are quick and

active in the testing and planting of new varieties. Cassava researchers, extensionists,

processors and trades must also be firmly linked and work together through the cassava

R&D network.

Money: Funding for cassava R&D activities have come from the goverment,

agricultural products trade companies, the agricultural extension budget, international

cooperation programs, various countries and from non-governmental organizations

(NGOs). Presently, funding for cassava R&D in Vietnam is very limited. However, it

has increased in recent years.

c. Constraints to cassava production

1. Crop competition: Sugarcane, rubber, coffee, fruit trees and cashew nuts are

competing with cassava, especially sugarcane. By the year 2000, Vietnam will try to

produce one million tons of sugar, 220-240 thousand tons of coffee, 180-200 thousand

tons of rubber and 120 thousand tons of cashew nuts. A total of 29 sugar factories are

operating to implement the planned objective. Rubber, coffee and fruit trees are

receiving big investments from the goverment. Competition from other, more valuable

crops may become a big problem for cassava production. The development of cassava

varieties suitable for each agro-ecological region and more productive cropping systems

are important to be able to make cassava an economically attractive crop.

2. Soil fertility degradation and erosion: In Vietnam, cassava is mainly grown on

grey Podzolic soils of low fertility and with slopes of 0-15%. In the past, fertilizer

application was very limitted. Growing cassava continuously in a certain area usually

leads to yield reductions. Studies on fertilizer application, legume intercropping and

suitable cultivation techniques for sloping soils are therefore required.

3. Genetic erosion: Cassava varietal improvement has greatly increased

production. However, the planting of new cassava varieties has created pressure to

eliminate old varieties and has narrowed the cassava germplasm base. Although no

serious outbreaks of pests or diseases have occured, genetic diversity should be

maintained in the cassava R&D program.

CONCLUSIONS AND RECOMMENDATIONS

Conclusions

1. Cassava varietal dissemination in Vietnam has made quick and reliable progress. The

99

Vietnam Root Crops Program in cooperation with CIAT, recently (1993-1996)

selected and recommended two new cassava varieties: KM60 (Rayong 60) and KM94

(MKUC 28-77-3). These were released for production by the Ministry of Agriculture

and Rural Development (MARD). The two varieties are now widely grown in an area

of about 15,000 ha in 1996. Advanced farmers, who obtained high yields and high

profits due to the growing of improved cassava varieties, have become good models

for other cassava growers to follow, resulting in the expansion of new varieties.

2. Experience in the linking of cassava R&D activities in Vietnam included the

establishment of the Vietnam Cassava Research and Extension Network and the

establishment of on-farm research and demonstration fields and Farmer Participatory

Research (FPR); these involve ten mutual link-up activities, called the "ten Ts" (in

Vietnamese).

3. Six essential conditions for successful cassava varietal dissemination in Vietnam

include: Materials, Markets, Management, Method, Manpower and Money ("six Ms")

Vietnam now has favorable conditions for cassava production. However, other

problems should be taken into account, such as crop competition (especially from

sugarcane); soil fertility degradation and erosion; and decreasing varietal diversity.

Recommendations

1 . Further strengthening of cooperation between the Vietnam Root Crops Program and

CIAT, not only in varietal improvement but also in the area of on-farm research and

transfer of technologies.

2. Use of biotechnology in cassava breeding and the multiplication of planting materials.

3. Studies on intercrop competition, soil fertility maintenance and erosion control, and

ways to enhance varietal diversity.

4. Trying to win financial support from cassava processing and trade companies (Vedan,

Ajinornoto, etc) and International Agricultural Research Organizations (CIAT, IDRC,

ACIAR) as well as from countries and non-governmental organizations.

REFERENCES

Ao Van Thinh. 1996. Cassava production, processing and marketing in Dong Nai province. In:

Pham Van Bien and Hoang Kim (Ed.). Cassava Breeding, Agronomy Research and

Technology Transfer in Vietnam. Proc. of a Workshop held in Ho Chi Minh city, Vietnam,

March 4-6, 1996. pp. 119-124. (in Vietnamese)

Carangal, V.R. 1990. Asian Rice Farming Systems Network and its activities. Rice Farming

Systems Technical Exchange, Vol. 1, No. 1:12-15.

Conway, C.R. 1986. Agro-ecosystem Analysis for Research and Development. Winrock

International, Bangkok, Thailand. 1 1 lp.

General Statistical Office. 1996. Statistical Year book 1996. Hanoi, Vietnam. Hoahg Kim, Tran

Hoang Kim, Tran Van Son, Nguyen Van Thang, Tran Ngoc Quyen and Ao Van Thinh. 1995. On

-farm research and transfer of technology for cassava production in Vietnam. In: R.H. Howeler

(Ed.) Cassava Breeding, Agronomy Research and Technology Transfer in Asia. Proc. 4th

Regional Workshop, held in Trivandrum, India. Nov 2-6, 1993. pp. 262-289.

100

Nguyen Hung Cuong. 1997. Some experiences of cassava planting on Grey Podzolic soil at

Traco village, Thong Nhat, Dong Nai. In: Agricultural Annual Report 1996. Proc. Vietnam

Cassava Workshop, held at Hung Loc Center, March 5-7, 1996. pp. 74-76. (in Vietnamese)

Nguyen Van Thang. 1996. Cassava in Vietnam: An overview. In: R.H. Howeler (Ed.).

Cassava Production, Processing and Marketing in Vietnam. Proc. of a Workshop held in

Hanoi, Vietnam. Oct 29-31, 1992. pp. 12-33.

Tran Ngoc Ngoan, Tran Ngoc Quyen, Hoang Kim and Kazuo Kawano. 1995. Recent progress

in cassava varietal improvement in Vietnam. In: R.H. Howeler (Ed.). Cassava Breeding,

Agronomy Research and Technology Transfer in Asia. Proc. 4th Regional Workshop, held

in Trivandrum, India. Nov 2-6, 1993. pp.253-261.

Tran Vien Thong. 1996. Cassava production, processing and marketing in Tay Ninh province. In:

Pham Van Bien and Hoang Kim (Ed.). Cassava Breeding, Agronomy Research and Technology

Transfer in Vietnam. Proc. of a Workshop held in Ho Chi Minh city, Vietnam. March 4-6,

1996. pp. 114-1 18. (in Vietnamese)

Zandstra, H.G., E.C. Price, J. A. Litsenger and R.A. Moris. 1981. A methodology for on-farm

cropping systems research. IRRI, Los Banos, Philippines.

101

BREEDING AND VARIETAL IMPROVEMENT OF CASSAVA IN INDIA

S.G. Nair, P.G. Rajendran, S.K. Naskar, M.T. Sreekumari, M. Unnikrishnan

and M.N. Sheela1

ABSTRACT

An analysis of the recent trend in cassava area, production and yield during 1993-96

revealed an impressive increase in Tamil Nadu, which is the predominant state where cassava is

grown as an industrial crop. Its present yield of 29 t/ha is the highest in the world. Even though

the overall national trend in cassava area and production is declining, India's current average yield

of 21 t/ha is also the world's highest.

In India, cassava breeding is mainly carried out at CTCRI in Thiruvananthapuram and

at its regional centre at Bhubaneswar. The All India Co-ordinated Research Project on Tuber

Crops, with eleven centres in the country, is also engaged in cassava improvement in a limited

way. The Tamil Nadu centre has recently identified a high yielding short duration variety, H-1 19,

while the Assam centre has identified two varieties, i.e. H-165 and Sree Prakash, suitable for the

region. The co-ordinating centres in Madhya Pradesh and Andhra Pradesh, along with the CTCRI

regional centre at Bhubaneswar, have been evaluating the promising exotic germplasm received

from the Thai-CIAT program. High root yields of more than 35 t/ha were recorded for some of

the CIAT selections, i.e. CMR33-67, CMR36-32, SM2077 and SM2090.

Attention is currently being given to the development of early maturing, good cooking

quality varieties, which can be harvested at sixth months, so that they can effectively be utilized

in cassava-rice double cropping systems as practised in Kerala. Three short-duration indigenous

clones, i.e. CI-649, CI-731 and CI-732, were identified, which are now in the pre-release stage.

These varieties are also included in the initial evaluation trial of the All India Co-ordinated

Research Project on Tuber Crops.

Breeding efforts are also focused on developing high yielding, high starch varieties for

areas like Tamil Nadu, Andhra Pradesh and Madhya Pradesh. A unique approach in this direction

is the production of "triploids". The triploids, possessing high yield combined with high starch

recovery, hold much promise to become popular in regions like Salem district of Tamil Nadu,

where the crop is grown for the starch industry. A triploid, 2/14, has already been proposed for

release under the name 'Sree Harsha' by the State Varietal Release Committee.

Studies are also in progress on the possibility of using sexual seed for the rapid

propagation and spread of cassava. Results indicate that even unselected first clonal progenies of

promising parents have a comparable root yield and dry matter production capacity as those of the

high yielding released varieties of cassava.

Cassava mosaic disease is still posing great problems in germplasm conservation. Use

of a nursery technique with three noded cuttings coupled with thorough screening and roguing of

CMD affected plants in the nursery and field was effective in the recovery and quicker

multiplication of symptom-free plants.

INTRODUCTION

Cassava (Manihot esculenta Crantz), popularly known in India as tapioca, is

reported to have been introduced into India sometime in the seventeenth century by

Portuguese traders who visited South India. Many of the "types" under cultivation today

have originated either by selection from the lines introduced in the early days from exotic

1 Central Tuber Crops Research Institute (CTCRI), Thiruvananthapuram, Kerala 695017,

India.

102

sources through chance seedling progenies or through natural mutations. The crop is

now grown in an area of 235 thousand hectares with an annual production of 5.34 million

tonnes (FAO, 1994). In India the cultivation of this crop is mainly concentrated in the

southern states, i.e., Kerala, Tamil Nadu and Andhra Pradesh, and to some extent in the

northeastern mountainous region. The three southern states together account for about

96% of the cassava area and 98% of production in India.

Area, Production and Yield

An analysis of cassava planted area and production shows an enormous increase

up to 1974/75 (0.39 million ha), after which it started declining fast until 1985/86 (0.27

million ha), followed by a slower decrease thereafter. The production area in Kerala

during the last three years (1991-94) is showing a slight decreasing trend (Table 1). The

major factor accounting for this decline in area is the shift in cropping pattern in Kerala

State, where plantation crops are starting to dominate the agricultural economy.

However, cassava production statistics for 1992-95 reveal that in Tamil Nadu, the

predominant state where cassava is grown as an industrial crop, the area, production and

yield have all increased impressively. The area under cassava in Tamil Nadu has

increased from 76,431 ha in 1990 to 85,543 ha in 1994 with a production of 2.856

million tonnes. The hybrids H-165 and H-226 occupy more than two thirds of the

cassava area in Tamil Nadu. Similarly, in Andhra Pradesh the same two varieties are

gaining popularity and are currently grown in an area of about 16,300 ha. In Assam, H-

165 and Sree Prakash have been found to be promising and have been recommended for

cultivation in the state in 1995. Tamil Nadu's present cassava yield of 29 t/ha is the

highest in the world. Even though the overall national trend in area and production is

declining, India's current cassava yield of 22 t/ha is the world's highest and more than

double that of the world average of 10 t/ha.

Table 1. Area, production and yield of cassava in Kerala.

Year

1991/92 1992/93 1993/94

Area ('OOOha) 141.88 135.03 130.99

Production ('000t) 2670.55 2629.13 2602.20

Yield (t/ha) 18.82 19.47 19.87

Source: Farm guide 1997, Govt, of Kerala.

103

Cropping Systems

The cropping system of cassava in Kerala has undergone a tremendous change,

from mainly upland monocropping to multiple cropping. The suitation is entirely

different in Tamil Nadu and Andhra Pradesh, where cassava is cultivated as an upland

monocrop. In Tamil Nadu, cassava is grown mainly as an irrigated crop under full-sun

conditions, except in Kanyakumari district, where it is grown as a rainfed crop under

both upland and lowland conditions (Ramanathan et al., 1990). In the irrigated area,

more than 75% of the area is planted with the high-yielding hybrid varieties H-165 and

H-226, whereas local varieties are grown in about 80% of the rainfed area. In the

irrigated and rainfed areas, Jan/Feb and April are the main months of cassava planting,

respectively. Similarly, there is a striking difference in terms of varietal dissemination

in Kerala vis-a-vis neighboring states of Tamil Nadu and Andhra Pradesh. While the

local varieties dominate (75% of the area) the cassava area in Kerala, in the other two

states mainly hybrids are grown. It was also observed that while there is great genetic

diversity in Kerala state, only a few varieties prevail in the other states.

Cassava Utilization and Varietal Distribution

Change in the utilization pattern of cassava roots have contributed to a great

extent to the spread of hybrid varieties and improved production technologies. In Kerala,

the major portion (> 70%) of cassava is used for direct human consumption, whereas in

Tamil Nadu and Andhra Pradesh 70% of production is utilized as industrial raw material

for the manufacture of starch and sago. There are about 1000 small-scale starch factories

in Tamil Nadu and about 45 in Andhra Pradesh, but in Kerala there are only 20 units.

With the wide-spread availability of cereals like rice and wheat resulting in a reduced

consumption of cassava as a cereal substitute, the crop's diversification to industrial

processing is the only alternative to sustain and increase the current level of production.

With the cassava-based industries picking up in Tamil Nadu and Andhra Pradesh, it is

no surprise that cassava hybrids have become popular in those states. Even in Kerala,

which has low industrial utilization of cassava, the yield of cassava has remarkably

increased from 7-8 t/ha in the 1950s to 18-19 t/ha in the 90s. This was achieved mostly

by low external-input improved production practices, along with a limited coverage of

high-yielding varieties.

There is a distinct variation in the preference for cassava varieties in different

regions of Kerala. A survey conducted by CTCRI revealed that the local varieties are

still very popular in Kerala state (68%) and their concentration is highest in central and

northern regions with a coverage of 80-90% of the area in Kottayam and Malappuram

districts (Table 2). In Trivandrum district, local varieties occupied about 53% of the

area and in Quilon around 36% (Ramanathan et al., 1989). The improved variety M-4

is very popular throughout the state and its dominance is especially noticeable in the

southern region.

104

Table 2. Varietal coverage of cassava in various districts of Kerala.

Varietal coverage in each district ( % of area planted)

Varieties Trivan

drum

Quilon Pathanama Kottayam

thitta

Malap

puram

Overall

Local varieties 52.76 35.55 12.65 81.65 90.51 68.78

Improved variety M-4 40.63 49.26 53.94 18.35 9.21 25.13

High-yielding varieties

H-165 4.68 2.25 5.45 - 1.65

H-226 0.15 10.80 22.02 - 0.15 3.27

Sree Visakham 1.22 1.07 - - 0.13 0.44

Sree Sahya 0.56 1.07 5.94 - - 0.73

Source: Ramanathan et al. , 1989

The utilization pattern of cassava in various districts of Tamil Nadu was observed

to have an influence on the varieties preferred for cultivation by the farmers. As most

of the production is used for direct human consumption in Kanyakumari district, good

tasting local varieties are preferred and are presently grown in about 80% of the area

(Table 3). The improved cassava variety M-4 had a coverage of only 6% of the area.

The high-yielding varieties H-165 and Sree Visakham (H-1687) were also rather popular

in this district and they accounted for about 13% of the area. With the concentration of

cassava-based starch and sago factories in and around Salem, there was a preference for

growing high-yielding varieties in the districts of Salem, South Arcot and Dharmapuri.

About 75% of the cassava area in each of these districts was found to be planted with the

hybrids H-165 and H-226. The remaining 25% of the area in Salem and Dharmapuri

was planted to the popular local variety "Burma" (Ramanathan et al., 1990).

Table 3. Varietal coverage of cassava in various districts of Tamil Nadu.

Varieties

Varietal coverage in each district (% of area planted)

Kanyakumari Salem South Arcot Dharmapuri Overall

Local varieties 80.21 27.83 7.65

Improved varities M-4 6.40 - 11.33

High-yielding variteties

H-165 4.76 5.15 57.03

H-226 - 67.02 23.99

Sree Visakham 8.63 - -

27.58

72.42

23.10

4.41

22.33

49.73

0.43

Source: Ramanathan et al. , 1990.

105

VARIETAL IMPROVEMENT

Germplasm Collection and Breeding

In India breeding research in cassava is mainly centered at the Central Tuber

Crops Research Institute (CTCRI), in Thiruvananthapuram, Kerala and at its regional

Centre in Bhubaneswar. The All India Co-ordinated Research Project on Tuber Crops,

whose headquarters is located at CTCRI, is also engaged in a limited way in cassava

improvement. Out of the eleven centers located at different Agricultural Universities and

at the ICAR Research Complex for the Northeastern Hill Region in Shillong, eight

centers are conducting cassava research.

Genetic variability is the essence of any plant breeding program. An assembly

of diverse genetic stocks of any crop is the raw material from which a new variety can

be moulded to suit the requirement of the farmers. A germplasm bank, including wild

relatives from within and outside the country, has been built up. The CTCRI germplasm

bank presently maintains 781 exotic and 806 indigenous acessions of cassava, as well as

eight wild species. The All India Co-ordinated Research centres maintain 765

indigenous accessions. Many of the local varieties of cassava under cultivation in Kerala

are either chance seedlings or are bud mutations selected for desirable characteristics and

maintained by farmers through vegetative propagation. Varieties best suited to the

requirements imposed by the local conditions are generally adopted and popularized in

various cassava growing areas. Moreover, the tendency of farmers to clonally multiply

the self-sown seedlings, if these are bestowed with any desirable attributes, particularly

better root characteristics, led to the addition of numerous varieties (Nair and Pillai,

1995). The majority of these types have local names, which generally indicate one of

the striking features of the plant.

A systematic evaluation of the genetic stocks has resulted in the identification of

several promising clones, which were later utilized either as parents in the intervarietal

hybridization or were released as varieties. As such, six varieties, i.e. H-165, H-226,

H-97, Sree Visakham, Sree Sahya and Sree Prakash, have been released from the Central

Tuber Crops Research Institute (Magoon et al., 1970; Jos et al., 1981). The Kerala

Agricultural University released a short duration cultivar called "Nidhi". Attention is

currently given for the development of early-maturing, good cooking quality varieties,

which can be harvested at six months, so that they can effectively be utilized in the rice-

cassava crop rotation program now in vogue in Kerala state. Research in this direction

has resulted in the identification from the germplasm bank of three short-duration

indigenous clones, i.e. CI-649, CI-731 and CI-732, which are now in the pre-release

stage in Kerala. These varieties are presently under initial evaluation in Andhra Pradesh,

Tamil Nadu and Madhya Pradesh under the All India Co-ordinated Research Project on

Tuber Crops.

106

Evaluation of CIAT Germplasm

Cassava seeds received from CIAT were initially screened at the Regional Centre

in Bhubaneswar. During the period from 1989-96, five sets of cassava botanical seeds

comprising 1 19 accessions were introduced from CIAT. Out of five sets, four sets of

seeds were evaluated preliminarily for yield characters and their reaction to diseases.

Germination percentage of seeds ranged from 0-100% . The highest average germination

was observed in the third batch (63.2%). Seedlings were evaluated in the field.

Harvesting was done at 7-10 months. The fresh root yield, along with the number of

selections made in each batch, are presented in Table 4.

Table 4. Fresh root yield obtained and the number of selections made in four

batches of cassava seeds received from CIAT.

Range in Average No.of

fresh root root yield selections

Batches yield (t/ha) (t/ha)

1" batch 0.00-24.69 5.43 1

2nd batch 4.94-43.02 8.11 1

3rd batch 8.64-43.20 19.45 9

4th batch 0.00-37.65 12.86 3

The root yield ranged from zero to 43.2 t/ha. The highest average yield of 19.45

t/ha was recorded in the third batch. A total of 14 high-yielding lines were selected

(Table 5).

The highest fresh root yield (43.2 t/ha) was obtained with CMR36-32, which was

not significantly different from that of CMR33-67 (43.02 t/ha). SM2077 and SM2090

were the next highest yielders, which recorded 37.65 and 35.18 t/ha, respectively.

Cassava Mosaic Disease (CMD) was not noticed at the Regional Center in Bhubaneswar,

but when these promising selections were transferred to the germplasm bank at CTCRI,

clear CMD symptoms were noticed in all the clones. The most important disease noticed

at the regional center was witches broom, which infected six accessions, i.e. CMR38-58,

CMR36-12, CMR36-38, CMR36-1 16, CMR36-71 and CMR36-73. Angular spot disease

and leaf spot disease were also noticed. The fifth set of seeds received from CIAT was

distributed to the Regional Center in Bhubaneswar as well as to the Co-ordinating Centers

in Madhya Pradesh and Andhra Pradesh for further evaluation and selection.

107

Table 5. Performance of 14 selections from cassava botanical seeds received from

CIAT.

Fresh root yield Root Root

Selections (t/ha) color" taste2)

OMR32-02 24.69 W NB

CMR33-67 43.02 w S

CMR36-32 43.20 w S

CMR36-34 22.21 w NB

CMR36-38 22.21 w NB

CMR36-116 25.91 w S

CMR36-123 28.50 w B

CMR36-159 22.21 w S

OMR36-28 23.44 w S

OMR36-31 28.38 w B

OMR36-73 23.45 w B

CM8619 25.43 w S

SM2077 37.65 w S

SM2090 35.18 w NB

»W = white

2>NB = not bitter; B= bitter; S1 = sweet

Production of Chromosomal Lines

Polyploidy breeding has great potential in crops where the economic produce is

a vegetative part, especially when it can be clonally multiplied. The somatic

chromosome number in cassava is relatively low (2n = 36), and hence the plant can

tolerate higher ploidy. So the production of induced tetraploids (4n = 72) and triploids

(3n = 54) constitute yet another basic approach to cassava improvement. Auto-

tetraploidy is being induced with colchicine in a wide range of genotypes, so as to

provide considerable variability at the polyploid level and allow a large-scale

hybridization program, followed by selection among polyploid types (Magoon et al.,

1969). The induced tetraploids so far produced have also been successfully utilized for

the production of triploids. Triploids are obtained by crossing induced tetraploids with

some of the cultivated cassava types; they were found to be superior to colchicine-

induced tetraploids in yield and sometimes outyielded diploids (Jos et al., 1987). The

triploid plants consistently showed higher root dry matter (DM) contents. The triploid

2/14 produced a higher root yield, dry matter (>45%) and recoverable starch content

(>35%) under multi-locational trials than the standard cassava check varieties. This

promising triploid was proposed for release to the State Variety Release Committee under

the name "Sree Harsha".

108

Enhancement of Carotene in Cassava

In most cassava clones, the flesh or the edible portion of the root is white and

devoid of any carotene. Yellow pigmented cassava varieties are cultivated in a limited

way in Colombia, the Philippines, Jamaica and in some south African countries (Oduro,

1981). Among a total of 654 accessions screened for carotene, 21 clones had yellow

flesh (Moorthy et al., 1990). The frequency of high-carotene clones were found to be

higher among the exotic collections. The carotene content ranged from 65 IU/100 g to

670 IU/100 g. An attempt was made to elevate the carotene levels through genepool

development from the existing genetic resources (Jos et al., 1990). By simple recurrent

selection the carotene content could be elevatd to 1500 IU in the first cycle, to 2200 IU

in the second, to 3217 IU in the third, and to 3985 IU/100 g in the fourth cycle (Table

6).

Table 6. Carotene content of cassava roots in the fourth cycle of recurrent selection.

Carotene content

Color of flesh No. of clones (IU/lOOg)

Orange 12 2000-3985

Yellow 9 2880-3925

Yellow orange 12 2200-3400

Interspecific Hybridization

Interspecific hybridization and genome analyses carried out on different crops

have opened up new avenues of improvement of crop plants and have successfully

contributed to the development of radically new and better types (Magoon, 1967). By

virtue of sharing a common genepool, cassava is easily crossable with a number of wild

species, and the occurrence of desirable genes makes interspecific hybridization one of

the most significant approaches in cassava germplasm development. However, the

absence of any wild species in Asia makes it difficult to procure the materials and to

maintain the species under our conditions; the lack of clonal propagation in some of

them, as well as their poor flowering, make the interspecific hybridization also rather

difficult. Though half a dozen species were used in the program, success could be

achieved only in four combinations, i.e. cassava x M. glaziovii, cassava x M. tristis,

cassava x M. flabellifolia and cassava x M. caerulescence. The hybrid, cassava x M.

caerulescence was found to be completely free of CMD symptoms. However, the

transfer of tolerance to the cultivated varieties was hindered by its erratic flowering and

female sterility. Interspecific back-cross (BC1 and BC2) populations were grown for

CMD screening and evaluation. Fifty seven per cent of the back cross population was

109

completely free of CMD symptoms. Twenty eight hybrids recorded yields ranging from

2.0-3.5 kg per plant.

True Cassava Seed Program

In the traditional production system it is difficult to bring large new areas under

cassava cultivation because of the low multiplication rate, bulkiness of planting material,

difficulty in transportation, rapid loss of viability of the planting material and the high

risk of introducing disease and pest problems (Rajendran and Ravindran, 1993). Studies

using sexual seeds have revealed that in the true seed program the multiplication rate

could be raised to above 1:150, as compared to 1:10 in the conventional method.

Promising cultivars have been identified which can produce more than 200 kg of sexual

seeds per hectare. At the time of transplantation of the seedlings in the field, the tap root

is cut and removed, which contributes to a high clonal yield at the seedling stage.

The first clonal progeny lines of promising parents had comparable root yield

potential and root dry matter production as those of the popular clonal varieties. These

studies indicate that cassava propagation from true seed has considerable potential in

some new industrial areas due to their high multiplication rate, ease in covering extensive

areas with lesser expense and comparable root yield and dry matter content. The

incidence of CMD is considerably reduced in these progeny lines.

Rapid Multiplication of CMD-free Plants

A quick method was developed at CTCRI for the multiplication of mosaic free

planting material. Symptom-free plants are selected from the field and stems are

collected. The stems are cut into small stakes having only 3 to 4 nodes. In the normal

practice, the setts are planted directly in the field. But in this new system, a nursery

stage is introduced before transplantation to field. The stakes are planted on nursery beds

and left to sprout. Screening for CMD symptoms is done as soon as leaf emergence has

started. Only symptom-free settlings are transplanted to the field at 25 days after nursery

growth. Roguing is also continued in the main field. At harvest, symptom-free stems

are again collected and setts are screened through this nursery technique before

transplanting to the field.

REFERENCES

Food and Agricultural Organization (FAO). 1994. Production Yearbook. Vol. 48

Jos, J.S., N. Hrishi, S.B. Maini and R.G..Nair. 1981. Two high yielding hybrids of cassava.

J. Root Crops 6:1-6.

Jos, J.S., K. Vijaya Bai and M.T. Sreekumari. 1987. Triploidy as a tool in cassava improvement.

Proc. Nat. Symp. Production and Utilization of Trop. Tuber Crops. CTCRI,

Thiruvananthapuram, India. pp. 7-19.

Jos, J.S., S.G. Nair, S.N. Moorthy and R.B. Nair. 1990. Carotene enhancement in cassava.

J. Root Crops: ISRC Nat. Symp. Special Edition: pp. 5-11.

Magoon, M.L. 1967. Recent trends in cassava breeding in India. Proc. 1st Symp. Int. Soc. Trop.

110

Root Crops. Trinidad, West Indies, pp. 110-117.

Magoon, M.L., J.S. Jos, K.N. Vasudevan and S.G. Nair. 1969. Cytomorphological studies on

induced polyploids of cassava. Genet. Iberica 21:27-47.

Magoon, M.L., S.G. Appan, R. Krishnan and R.C. Mandal. 1970. Some promising high yielding

hybrids and selections of cassava. SABRAO Newsletter 2: 19-26.

Moorthy, S.N., J.S. Jos, R.B. Nair and M.T. Sreekumari. 1990. Variability of/? carotene content

in cassava germplasm. Food Chemistry 36:233-236.

Nair, S.G. and Santha V. Pillai. 1995. Cassava breeding in Kerala. Proc. Seminar on Crop

Breeding in Kerala. Dept. of Botany, University of Kerala. pp. 49-59.

Oduro, K.A. 1981. Some characteristics of yellow-pigmented cassava. In: Tropical Root Crops:

Research Strategies for the 1980s. Proc. IDRC. Ottawa, Canada. 163e. pp. 42-44.

Rajendran, P.G. and C.S. Ravindran. 1993. Cassava cultivation through true seed propagation.

J. Root Crops 19(2):81-88.

Ramanathan, S., M. Anantharaman and T.K. Pal. 1989. Cassava in Kerala: A study on the

present status and varietal distribution. J. Root Crops 15(2): 127-131.

Ramanathan, S., M. Anantharaman and T.K. Pal. 1990. Cassava in Tamil Nadu: A study on the

present status and varietal distribution. J. Root Crops 16(2): 83-86.

Ill

CASSAVA RESEARCH PROGRAM AT TAMIL NADU AGRICULTURAL

UNIVERSITY (TNAU) IN INDIA

S. Thamburaf

ABSTRACT

Cassava is cultivated in Tamil Nadu in an area of 85,983 ha with an annual production

of about 2.5 million t of roots (1993-94). At the world level, Tamil Nadu ranks first in yield,

with 28.7 t/ha, as compared to the Indian average of 22.8 and a world average of 9.6 t/ha. In

Tamil Nadu cassava is grown mainly in Salem and Kanyakumari districts located in the dry

western zone (60% irrigated and 40% rainfall) and the high rainfall southern zone (mostly

rainfed), respectively. The area under cassava is increasing in other districts of Tamil Nadu as

well.

With respect to varieties, about 50% of the total area is grown with high-yielding

varieties, like H-226 and MVD-1 in most areas of Salem district, and with Co-1, Co-2, Co-3 in

different parts of Tamil Nadu. Locally adapted and traditional varieties, like Burma and Malabar,

are still under cultivation, but they are low yielding and susceptible to cassava mosaic disease.

The cassava germplasm collection has now increased to 480 accessions, including some

CIAT clones. Two early maturing clones were identified, i.e., H-1 19 from CTCRI, Trivandrum,

and Co-3 developed by Tamil Nadu Agr. Univ. in Coimbatore. The crop duration is 7 1/2 to 8

months with a high yield of 32 and 35 t/ha, respectively, and a starch content of about 30 % . For

the high rainfall zone of Kanyakumari district, the local clone Adukkumuttan performs well,

giving a 15 to 28% increase in yield compared to the released varieties. For coastal areas of

South Arcot district, two clones, i.e. ME-46 and ME-10, were shown to be better, with a yield

of 44 t/ha; these are now under further evaluation. Under the Asian cassava breeding network

a total number of 85 hybrid progenies were received from CIAT/Colombia and the Thai-CIAT

program. Preliminary evaluation has indicated that a few clones have high root yields of more

than 5 kg/plant, high starch content of over 35%, field tolerance to mosaic virus and a shorter

crop duration of 7 to 8 months.

The optimum fertilizer rate for Co-3 cassava under irrigated conditions was found to be

60:60:120 kg N-P2O5-K:O/ha, which increased the yields by 36% over the control. For the

recently developed short-duration clones, like H-1 19, CI-590and S-856, under irrigated conditions

the optimum spacing and fertilizer requirements are 75 x 75 cm and 75:25:75kg N-P2O5-K2O/ha,

respectively. Application of Azospirillum inoculum at 2 kg/ha as basal dressing with

recommended fertilizers, combined with three foliar sprays of zinc sulfate (0.5%) and iron sulfate

(1.0%) at 60, 75 and 90 days after planting, increased the root yield and starch content of Co-1

and Co-2 varieties. Under abundant water supply, cassava intercropped with groundnut can be

irrigated at 0.6 IW/CPE ratio with an interval of 12 days and the application at 10 t/ha of coconut

husk waste. Under limited water supply, irrigation may be reduced to 0.45 IW/CPE ratio with

an interval of 16 days.

INTRODUCTION

In India, the major cassava growing states are Kerala and Tamil Nadu. In Tamil

Nadu cassava is an industrial crop grown in an area of about 86 thousand ha (1994/95)

with a production of 3.24 million tonnes of roots per year (Figure 1). Tamil Nadu

' Head, Horticultural College and Research Institution, TNAU, Coimbatore - 641 003, Tamil

Nadu, India.

112

accounts for 33% of the area and 46% of cassava production in India. The area has

increased considerably during the last ten years because of the industrial exploitation of

the crop. In 1986/87 there were only 48 thousand ha with a production of 1.8 million

tonnes. The crop has now acquired a status of one of the important commercial crops

in the state. Tamil Nadu is blessed with varied soil and climatic conditions that are well

suited for cassava growing. Already Tamil Nadu has the highest cassava yield, with a

range from 14.76 to 60.33 t/ha and a mean of 37.72 t/ha. This could be attributed to the

growing of high-yielding varieties released by CTCRI in Trivandrum and by Tamil Nadu

Agricultural University, and the adoption of recommended crop production technologies,

both under irrigated and rainfed conditions. The Indian average cassava yield is 22.87

t/ha, while it ranges from 5.1' to 14.4 t/ha in most other cassava growing countries.

Tamil Nadu state is divided into seven agroclimatic zones and the major

traditional cassava growing areas in the western part of the state are the districts of

Salem, South Arcot Vallalar and Dharmapuri (60% irrigated and 40% rainfed) and the

southern district of Kanyakumari (mostly rainfed) (Figure 2). There are about 800 sago

and starch factories in and around Salem, South Arcot Vallalar and Dharmapuri districts

which depend on cassava roots. The number of factories in Salem district alone is 650.

It is estimated that 60% of the cassava starch produced in India is from Salem district.

This district accounts for 44% of area and 47% of production of cassava in Tamil Nadu.

Because of ease in cultivation, few pests and diseases problems, drought tolerance and

the increase in root prices, the area under cassava is also increasing in other districts of

Tamil Nadu, i.e. in Periyar, Tiruchirapalli and Coimbatore districts.

Even though the area is increasing, the production is not sufficient to meet the

demand of the factories, which operate only about six months of the year. The industries

operate at only 50% of capacity. Hence, there is a need to increase the cassava area and

production in Tamil Nadu.

There is also scope for further increases in yield through the development of new

varieties with high yield and higher starch content and the recommendation of zone-

specific packages of practices, especially suited for rainfed culture of cassava.

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RESEARCH ACCOMPLISHMENTS

Earlier Research on Cassava

As far as the varietal situation is concerned, about 50% of the total area is grown

with high-yielding varieties like H-226, MVD-1 (in most areas of Salem district), and

Co-1 and Co-2 and Co-3 in different parts of Tamil Nadu. The salient features of these

varieties are shown in Table 1.

Another improved variety MVD-1 (Mulluvadi 1) was released during 1983 by

the State Department of Horticulture through clonal selection. It yields 34.5 t/ha in a

duration of nine months. The roots contain 35% starch. It is a non-branching type and

exhibits field tolerance to mosaic virus. Locally acclimatized and traditional varieties like

"Burma" and "Malabar", are still under cultivation, but they are low-yielding and

susceptible to CMD.

The recommendations on agronomic requirements and utilization of cassava,

based on earlier field experiments at TNAU are: 1) use of single-bud setts for rapid

multiplication, 2) dipping the setts in a superphosphate slurry, 3) use of ridges and

furrows (75 x 90 cm) for irrigated crop; bed system for rainfed crop (60 x 60 cm); and

mound system (90 x 90 cm) for high-rainfall zones, 4) application of 25 t/ha of FYM

with 50:50:100 kg/ha of N-P205-K20 for irrigated crop, 5) growing of intercrops like

onion and blackgram, 6) use of growth hormones TIBA at 1000 ppm, Alar at 1000 ppm

or bioregulator Ethrel at 500 ppm, 7) irrigating cassava at 60% moisture with a

consumption of water of 1607 mm and witholding water one month before harvest, 8)

allowing two shoots per sett, 9) adoption of no-tillage method with application of organic

mulch of banana pseudostem or cumbu stalks, 10) pre-emergence herbicide application

of pendemethalin at 1.0 kg a.i./ha, followed by two hand weedings, 1 1) utilizing cassava

leaves for rearing silkworm, 12) using dry flour of cassava leaves in cattle or pig feed,

13) utilization of seed for extraction of edible oil, 14) use dry cassava chips or pellets as

cattle feed, 15) development of recipes for Indian foods like pergath, bonda, stuffed

parota, sweet balls, susiam, munthirirotu, idly, halva, idiappam, vermicelli, ready mixes

of soji and bakery products, 16) protein enrichment of cassava vermicelli by the

incorporation of green gram, bengal gram or soybean flour and 17) development of

animal feed pelletization.

Earlier work on mutation breeding indicated the possibility of inducing variability

for higher yield, compact growth habit, early maturity, higher starch content and lower

HCN. A protocol for in-vitro propagation of cassava has been developed. Research on

the use of true cassava seed indicated that soaking the seeds in potassium nitrate solution

(0.5%) for 24 hours prior to planting enhanced the germination as well as the seedling

vigor. The performance of plants raised from true cassava seeds is being studied.

116

Table 1. Salient features of cassava varieties developed by Tamil Nadu Agric.

University.

Particulars Co-1 Co-2 Co-3

Year of release 1974 1984 1993

Root yield (t/ha) 30.11 37.65 42.58

Crop duration (days) 255-270 255-270 240

Starch content (%) 35.00 34.35 35.60

Taste Sweet Sweet Sweet

Color of skin Brownish white Brownish white Dark brown

Color of flesh White White White

Incidence of mosaic disease Low Very low Very low

Branching habit Non-branching Branching at

later stage

Branching

Current Research on Cassava

1. Crop Improvement

For any breeding program to succeed, the availability of diverse genetic material

is important. With that in view, attempts were made to enrich the cassava collections.

The germplasm bank at TNAU has presently the following number of accessions:

Indigenous 115

From CTCRI, Trivandrum 30

From CIAT/Colombia and the Thai-CIAT program 525

Total 670

Polyploidy breeding has been reported to have many advantages in cassava. The

two promising triploids developed at CTCRI, Trivandrum, were tested for two years at

Coimbatore. The results have indicated that the triploid variety 2/14 was similar to the

check Co-2 with respect to root yield, DM and starch content. Results of the triploids

being tested under Salem conditions are shown in Table 2.

Developing varieties with a shorter crop duration is another important objective

in cassava breeding. Four short duration clones, i.e., H-1 19, CI-590, S-856 and H-5/78,

were evaluated for three seasons. The results indicate that the clones H-1 19, CI-590, S-

856 and H-5/78 have a shorter crop duration of 7 1/2 to 8 months. Among these four,

H-1 19 recorded a significantly higher average root yield of 36.43 t/ha. It is a non-

branching clone. However, the clone H-1 19 was found to be susceptible to CMD under

Coimbatore conditions (Table 3). Good performance of H-1 19 has also been reported

by Nanda et al. (1996) under Madhya Pradesh conditions, a non-traditional area of

cassava cultivation in India.

117

Table 2. Performance of triploid cassava varieties in Salem, Tamil Nadu, India.

Root

dry Root

Root yield (t/ha) matter starch

content

(%)

content

Clones 1993 1994 Average (%)

76/9 (CP.4(2x) x S-300 (4x) 19.5 18.3 18.9 45.8 34.2

2/14 (CP.2 (2x) x H-2304 (4x) 28.6 25.3 27.0 48.2 35.6

H-1687 30.0 23.8 26.9 39.1 30.2

H-2304 18.5 20.6 19.6 41.6 31.5

M-4 22.4 24.5 23.5 38.1 30.0

Co-2 28.4 27.1 27.8 48.6 35.0

SED 0.887 0.957 0.922

CD (P=0.05) 2.14 2.310 2.230

Table 3. Performance of short-duration cassava clones in Coimbatore, Tamil Nadu,

India.

Root yield (t/ha) Crop Root

duration

(days)

starch

contentClones 1987/88 1988/89 1989/90 Average

(%)

HI 19 34.3 38.3 36.7 36.43 230 32.0

CI-590 20.4 28.7 26.9 25.33 240 33.0

S-856 29.5 30.7 30.7 32.96 230 30.8

H-5/78 13.9 27.1 30.6 23.06 240 30.6

SED 1.43 2.27 1.80

CD(P = 0.05) 4.02 6.35 3.78

Based on these results, the best two clones, H-119 and S-856, were tested in

multi-locational trials in farmers' fields in Coimbatore using Co-2 as a check. Again,

the clone H-119 had a significantly higher yield of 30.56 t/ha, a 13.0% increase over Co-

2. The root yield of S-856 was 27.80 t/ha, which was not significantly different from

that of Co-2. However, with regard to quality, Co-2 registered better consumers'

preference (80.2%) than H-l 19 (78.5%) and S-856 (78.0%). The mosaic incidence was

118

also higher in H-119 and S-856 (65.0 and 61.2%, respectively) as compared to that of

Co-2 (5.2%).

For the high-rainfall zone of Kanyakumari district, the local clone,

Adukkumuttan performs well with 20-28% higher yields than the released varieties.

For coastal areas of South Arcot Vallalar district, two clones, i.e., ME-46 and

ME-10, were found to be the best with a mean root yield of 44 t/ha; they are now under

further evaluation.

Cassava is grown on a large-scale in Salem district of Tamil Nadu. Sofar,

varieties developed at CTCRI, Trivandrum, and at TNAU, Coimbatore, have been

introduced. However, there is a need to develop or identify varieties more suited to the

conditions that exists in this altogether different environment. With this objective, a total

of 13 clones were tested during 1995 in a farmer's field in Salem. Among the clones,

S-1315 performed best with a root yield of 4.5 kg per plant, followed by CE-22 (3.5 kg)

and H-2304 (3.0 kg). There was no virus incidence in the clones H-97, CI- 167, H-1 19,

H-2304 and Co-2 under field conditions.

There exists a possibility of introducing true cassava seeds for commercial

cultivation in Tamil Nadu where CMD is noticed on a large scale. To elucit basic

information, research was conducted at the Department of Seed Technology of Tamil

Nadu Agricultural University. The seed maturation studies conducted in true cassava

seed have indicated that seeds attained physiological maturity 60 days after flowering

under Coimbatore conditions. The physical index of maturity was the color change from

green to yellow. Delayed harvest resulted in the shattering of the seeds (Nepolian,

1995). Germination studies on true cassava seeds have brought out that soaking of seeds

in 0.5% KN03 solution for 24 hours prior to planting resulted in 94% germination.

Storage studies revealed that cassava seeds can be stored at 6.26% moisture for ten

months under ambient conditions without a decrease in germination. Rajendran et al.

(1993) reported that the seeds could be stored for four to six months with good

germination, while the seed viability reduced thereafter under Kerala conditions. Sowing

at 2 cm depth in soil with 50% water holding capacity was observed to be optimum

(Nepolian, 1995). Studies on the physiology of root development in plants raised from

true cassava seed is in progress at the Horticultural College and Research Institute, Tamil

Nadu Agricultural University, Coimbatore.

2. Evaluation of CIAT Hybrid Clones

Under the International Evaluation Network Programme, seeds of 109 cassava

hybrids were received from CIAT/Colombia and from the Thai-CIAT program during

1993. The seeds were sown in polybags in the nursery and the seedling progenies were

transplanted. Among 109 hybrids only 91 established in the field. A total number of

525 clonal progenies were forwarded to further clonal generations. From the seedling

progenies, stakes were prepared and clonal progenies were evaluated for two clonal

119

generations during 1995 and 1996. The results on the variability of the progenies for

morphological traits, root yield, harvest index, starch content and reaction to cassava

mosaic disease are presented in Tables 4 and 5. Based on the performance of these

clonal progenies, a total number of 20 and 38 clonal progenies were selected during 1995

and 1996, respectively. The data on root yield along with other traits are presented in

Tables 6 and 7.

The following 21 CIAT hybrid clones were selected for non-branching habit,

which will be tested later for high density planting. The figures in parenthesis indicate

the number of clones in each hybrid exhibiting non-branching habit.

CM8487 (3), SM1450(2), SM1454(8), SM1520(2), SM1542(13), SM1557(1),

SM1636 (1), SM1673 (2), SM1679 (2), SM1784 (8), SM1789 (10), SM1791 (4),

SM1858 (1), SM1864 (3), SM1969 (3), OMR36-05 (12), SM1780 (2), SM1883

(3), SM1890 (3), SM1891 (6) and SM 8208 (4).

Based on the performance of two seasons' clonal generations, the following 16

clones were selected for short-duration (early harvestability), ranging from 205 to 225

days. The figures in parenthesis indicate the clone number (ME) of each hybrid.

SM1475 (359), SM1858 (578), SM1470 (356), SM1544 (426), SM1665 (476),

SM1475 (358), SM1454 (323), SM1774 (521), SM1432 (310), SM1454 (321),

SM1447 (314), SM1460 (349), SM1523 (398), OMR36-4-1 (633), SM1787

(245), and SMI670 (200)

Since flowering is an important trait for breeding programs, the CIAT hybrid

clones were also evaluated for their flowering habit. Among the clonal progenies, a total

number of 33 and 48 clones flowered during 1995 and 1996, respectively. Out of these,

the following 12 clones flowered uniformly during both years. The figures in parenthesis

indicate the clone number (ME) of each hybrid.

SM1437 (175), SM1765 (208), SM1787 (242), SM1788 (249), SM1789 (250),

SM1789 (255), SM1447 (312), SM1519 (375), SM1521 (383), SM1564 (445),

SMI789 (566) and SMI 858 (578)

The third clonal generation is in the field. Based on the performance of the

clonal progenies, a few selected ones will be forwarded for regional evaluation trials in

order to identify promising ones and to release as a new variety suited for cultivation in

Tamil Nadu.

3. Crop Production Research

Nutrient management is an important aspect in cassava and studies on this aspect

have provided useful results. Application of 10 tonnes of FYM + 60:75:100 kg/ha of

N-P2O5-K20, 2 kg/ha of Azospirillum, combined with three foliar sprays of 0.5% zinc

sulfate and 1 % ferrous sulfate (60, 75 and 90 days after planting) resulted in root yields

of Co-1 and Co-2 varieties of 34.57 and 35.43 t/ha, respectively (Table 8). The starch

content was also the highest (39.98%) in Co-2 in this treatment. There was no

120

significant difference in the HCN content of the root parenchyma. A quantity of 2 kg

of Azospirillum inoculum is to be mixed with one liter of water, made into a slurry and

the basal 1/3 of the stake is to be dipped for 20 min in the slurry before planting.

Table 4. Range in plant characteristics of hybrid clones received from CIAT

1995 1996

Characters Range Mean CV

(%)

Range Mean CV

(%)

Plant height (cm) 121.3-291.6 210.75 13.1 118.8-296.2 205.86 9.1

Stem girth (cm) 2.0-11.6 7.21 15.2 2.1-17.2 8.06 14.8

Root length (cm) 6.8-45.2 18.18 14.0 6.1-61.0 23.06 16.2

Length of peduncle (cm) 0.0-4.6 1.20 8.5 0.0-5.9 1.36 9.6

Dry matter content (%) 18.2-37.5 26.52 16.2 17.5-40.2 29.22 17.2

Starch content (%) 21.0-36.8 31.20 10.6 22.0-37.2 30.51 11.2

HCN content (mg/kg) 12.2-40.3 22.56 11.2 14.5-41.6 23.19 10.4

Harvest index (%) 32.0-66.7 47.07 12.3 28.1-59.0 43.71 10.2

Fresh root yield (kg/plant) 1.3-3.5 2.41 19.9 1.2-4.9 2.27 28.5

Foliage weight (kg/plant) 1.3-5.1 2.63 26.2 1.6-5.2 2.77 26.7

From another study, the optimum fertilizer dose for the newly released cassava

variety Co-3 under irrigated conditions was determined to be 60:60: 120 kg/ha of N-P2O5-

K2O, which increased the root yield by 36% over the control.

A trial was conducted for three seasons to assess the fertilizer and spacing

requirements for the short-duration clones H-1 19, CI-590 and S-856. The results indicate

that all three short-duration clones produced higher yields at a closer spacing of 75 x 75

cm and a lower dose of fertilizers of 75:25:75 kg/ha of N-P2O5-K20. Besides the root

yield, the dry matter and harvest index were also increased. The interaction effects were

significant, and irrespective of the fertilizer dose, closer spacing resulted in higher root

yields.

Nitrogen use efficiency by crops is of major interest in the tropics. Nitrogen is

subject to leaching, denitrification and volatilization, which makes it unavailable to

plants. Hence, studies were conducted under irrigated conditions on the use of

nitrification inhibitors with nitrogenous fertilizers. The results of the trial on the use of

slow-release fertilizers conducted for three seasons has indicated that the root yield in

cassava was increased by all the four slow-release fertilizers (Table 9). However, a

significantly higher average yield of 34.8 t/ha was obtained with the application of neem-

coated urea; the next best treatment was sulfur-coated urea (32.3 t/ha).

121

Table 5. Evaluation during 1995 and 1996 of plant characteristics of cassava hybrid

clones received from CIAT.

Character Variations 1995 season (%) 1996 season (%)

Vigor Very poor 2.80 2.50

Poor 9.21 8.00

Intermediate 50.50 55.80

Good 26.20 27.20

Very good 11.29 6.50

Flowering Nil 85.21 89.87

Few 2.50 2.12


Abundant 3.11 2.80

Plant height Dwarf (< 200 cm) 49.64 44.85

Medium (200-300cm) 46.04 49.47

Tall (> 300cm) 4.32 5.68

Stem girth Thin (<5cm) 5.60 55.47

Medium (5- 10cm) 84.20 85.05

Thick (> 10cm) 10.20 9.48

Branching habit Non-branching 69.20 68.14

Early-branching 18.50 20.04

Late-branching 12.30 11.82

Lodging None or light 40.80 42.55


Severe 4.00 5.20

Petiole color Pink 58.00 58.65

Green 37.50 36.71

Pink + Green 4.50 4.64

Emerging leaf color Green 61.20 61.18

Pink 38.80 38.82

Root length Short ( < 20cm) 36.20 39.08

Intermediate (20-30cm) 45.10 42.36

Long ( > 30cm) 18.70 18.76

Length of peduncle Nil 85.20 66.65

Short (< 3cm) 5.60 25.25

Intermediate (3-5cm) 5.26 5.04

Long (>5cm) 3.94 3.06

Root color White 10.00 10.08

Light brown 24.60 23.84

Dark brown 65.40 66.08

Flesh color White 69.00 69.15

Cream 28.90 28.66

Yellow 2.10 2.19

122


Character Variations 1995 season (%) 1996 season (%)

Root shape Conical 2.50 2.41

Conical cylindrical 38.00 38.51

Cylindrical 56.00 55.14

Irregular 3.50 3.94

Constrictions None or few 80.00 82.05


Several 3.20 4.38

Foliage and root Very good 45.00 42.80

evaluation Good 25.00 20.60

Regular 15.20 18.20

Bad 7.58 8.00

Very bad 7.22 10.40

Dry matter High (> 30%) 26.10 22.15

Medium (20-30%) 40.80 42.63

Low (<20%) 33.10 35.22

Starch content High (> 30%) 23.20 24.10

Mekium (25-30%) 52.10 53.26

Low (<25%) 24.70 22.64

HCN content High(>30mg/kg) 30.00 31.65

Medium (20-30mg/kg) 45.28 40.15

Low (<20mg/kg) 24.72 28.20

Harvest index Low (<0.40) 20.95 38.35

Medium (0.40-0.50) 54.36 30.40

High (> 0.50) 24.69 31.25

Fresh root yield <2 55.67 62.88

(kg/plant) 2-3 33.49 19.00

3-4 8.13 9.17

>4 2.71 8.95

Incidence of CMD 0 (no CMD) 2.60 2.56

(score) 1 0.50 0.24

2 1.21 1.73

3 7.90 8.64

4 34.50 31.75

5 53.29 55.08

123

Table 6. Yield data of selected CIAT hybrid cassava progenies" grown at TNAU in

1995.

CIAT Clone Plant Root yield Foliage Harvest Starch

hybrid No. No. height (kg/plant) weight index content

(ME) (cm) (kg/plant) (%)

OMR36-42 641 297 5.6 5.20 0.52 36.25

OMR36-05 671 288 4.4 8.30 0.35 35.20

OMR36-67 645 238 4.0 5.10 0.44 35.15

SM7564 656 304 4.9 4.00 0.55 36.00

CM8487 296 175 3.5 2.70 0.69 33.50

SMI 432 306 127 3.0 1.90 0.68 33.10

SM1432 310 231 3.2 3.30 0.49 34.10

SM1456 332 205 3.0 3.25 0.48 33.90

SM1460 347 270 3.2 3.20 0.50 33.90

SM1470 356 270 3.1 3.20 0.49 33.20

SM1673 397 151 3.1 2.25 0.58 33.30

SMI 789 564 185 3.7 3.20 0.53 35.30

SMI 855 572 210 3.1 5.20 0.37 34.30

SMI 858 578 245 4.0 3.00 0.57 36.80

OMR36-05 618 258 3.8 4.10 0.48 35.00

OMR36-05 625 259 3.9 2.60 0.60 35.12

OMR36-42 654 248 3.6 6.00 0.37 34.86

OMR36-42 637 266 3.5 4.20 0.45 34.90

OMR36-42 640 240 3.0 2.60 0.54 33.85

SM1564 657 240 3.2 4.10 0.44 33.90

"clonal progenies obtained from sexual seed received from CIAT in 1993.

124

Table 7. Yield data of selected CIAT hybrid cassava progenies" grown at TNAU in

1996.

CIAT Clone Plant Root yield Foliage Harvest Starch

hybrid No. No. height (kg/plant) weight index content

(ME) (cm) (kg/plant) (%)

SM1444 183 270 6.0 3.65 0.62 35.00

SM1414 186 350 7.3 9.00 0.45 35.62

SM1432 302 217 4.1 4.60 0.47 34.80

SM1432 310 250 5.2 6.20 0.46 36.10

SMI 447 314 267 5.1 7.50 0.40 35.50

SM1454 321 255 5.2 4.20 0.55 35.90

SM1454 343 205 5.5 3.40 0.55 35.96

SM1460 346 225 5.1 4.85 0.46 35.90

SMI 460 344 256 5.1 2.70 0.57 30.90

SMI 470 356 226 7.0 6.00 0.54 35.50

SM1475 358 266 5.6 7.50 0.57 36.20

SM1475 359 323 9.0 10.70 0.46 36.80

SM1521 384 185 4.3 5.70 0.43 34.80

SM1523 398 240 5.5 4.30 0.56 35.90

SMI 544 426 195 5.8 1.80 0.76 35.30

SM1545 430 215 5.0 7.00 0.42 36.20

SM1573 464 110 4.0 2.50 0.62 34.80

SM1665 476 225 5.8 4.50 0.56 35.20

SM1670 200 168 4.9 3.40 0.59 35.60

SM1670 201 240 4.1 2.00 0.67 34.60

SM1718 218 260 4.3 5.60 0.43 35.00

SM1774 269 285 9.8 5.20 0.65 36.40

SMI 774 521 204 5.5 4.80 0.53 35.00

SM1783 222 228 4.8 4.70 0.51 35.50

SM1784 539 295 4.5 4.00 0.53 34.90

SM1784 541 180 4.0 0.85 0.82 34.00

SMI 784 551 220 4.6 4.70 0.50 35.00

SM1787 240 277 4.0 4.50 0.41 34.00

SM1787 243 200 4.2 3.70 0.53 34.25

SM1787 245 240 4.8 3.70 0.36 35.00

SM1787 256 295 4.1 5.00 0.45 34.60

SM1789 251 290 4.1 5.20 0.44 34.60

SMI 855 573 220 4.6 2.20 0.68 34.80

SM1858 578 245 8.5 5.60 0.60 36.20

SM1883 265 267 8.0 6.00 0.57 36.00

SMI 890 270 280 7.0 3.90 0.64 35.00

SM1891 278 268 4.1 4.90 0.46 34.82

OMR36-41 635 178 5.0 2.80 0.63 35.10

"clonal progenies obtained from sexual seed received from CIAT in 1993.

125

Table 8. Effect of micronutrients (Zn and Fe) and biofertilizer (Azospirillum) on the

yield and starch content of two cassava cultivars grown at TNAU.

Fresh root yield (t/ha) Starch content (%)

Treatments Co-1 Co-2 Co-1 Co-2

Control (fertilizers only) 16.50 22.40 32.60 34.14

Fertilizers + Zn + ¥e+ Azospirillum 34.57 35.43 35.16 39.98

Earlier studies on intercropping indicated that Bellary onion (Allium cepa var.

cepa) and blackgram were suitable intercrops for cassava. In a separate study by

Mohammed Yassin (1995) conducted for two years on the N management and

intercropping in cassava, it was found that growing vegetable cowpea or sunhemp as

intercrops and incorporating the haulms into the soil increased the root yield of cassava

from 18.87 to 45.0 t/ha in the first experiment, and from 13.45 to 35.63 t/ha in the

second experiment. The cost benefit ratio was higher, i.e. 1:3.8 and 1:2.8 during the

first and second years, respectively, as compared to monocropped cassava. The starch

and DM content of the root was also increased. The effect was more pronounced when

neem-coated urea or prilled urea + Azospirillum at the rate 2 kg/ha were applied.

Ayyaswamy (1994) conducted experiments on irrigation scheduling and inter

cropping systems in cassava. The results have indicated that under abundant water

supply, cassava grown as an intercrop in groundnut and irrigated at 0.6 IW/CPE ratio

with an interval of 12 days and with coconut fibre waste (as soil amendment) applied at

10 t/ha increased the root yield and net returns per hectare. Under limited water supply,

the same treatment with a change in irrigation scheduling at 0.45 IW/CPE ratio, applied

at an interval of 16 days, was found optimum. There was improvement in both dry

matter and starch content of the roots.

4. Post Harvest Technology

Research programs are in progress at Tamil Nadu Agricultural University on the

processing of cassava roots. Susheela Thirumaran and Aruna Seralathan (1996)

conducted experiments on the production of cassava-based defatted soyflour noodles. The

results showed that the noodles had desirable properties, such as a more than six months

shelf life and significantly high acceptability scores, while providing 340 kilo-calories of

energy and having 16% protein. They have suggested that extrusion of nutritious noodles

can be initiated as a commercial venture for school lunch programs.

126

Table 9. Effect of the application of slow-release nitrogen fertilizers on the yield of

cassava grown in TNAU.

Root yield (t/ha)

Treatments 1992/93 1993/94 1994/95 Average

Prilled urea 30.3 31.4 33.1 31.6

Urea super-granule 29.6 30.8 31.2 30.5

Neem-coated urea 33.5 34.2 36.7 34.8

Sulfur-coated urea 30.5 32.7 33.6 32.3

Tar-coated urea 28.8 27.6 30.8 29.1

Control 24.7 26.1 27.9 26.2

SED 0.688 0.456 0.513

CD(P= 0.05) 1.480 0.970 1.262

At Tamil Nadu Agricultural University, the College of Agricultural Engineering

is involved in the development of machinery for cassava harvesting and processing. A

root puller (harvester), chipper, peeler, mechanical stirrer for starch settling tanks, sago

roaster and pelletizer are some of the pieces of equipment developed for use in small-

scale industries.

THRUST AREAS AND SUGGESTIONS

1 . Cassava in Tamil Nadu is affected by mosaic virus disease as a result of which the

yield is considerably reduced. The incidence is greater in Salem, South Arcot Vallalar

and Dharmapuri districts. Resistant varieties are to be developed. It is observed that

there are variations in the susceptibility of clones to cassava mosaic disease in different

agro-climatic zones. Some of the clones susceptible at Coimbatore are free from CMD

at Salem or Kanyakumari in Tamil Nadu. It is suspected that there may be strains or

races of the virus which needs to be investigated.

2. In Salem district, there are location-specific problems in cassava fields, like twisting,

knotting and splitting of roots, which affect the root yield and industrial quality. The

reasons are to be investigated and suitable remedial measures suggested.

3. Occurrence of root rot caused by Sclerotium rolfsii has recently been noticed in some

locations of Salem district and resistant varieties and suitable management practices are

to be developed.

4. In most of the locations cassava is grown as a rainfed crop. Unlike Kerala, the annual

amount of rainfall is only 800-900 mm. There is a need to develop varieties adapted to

rainfed cultivation and a package of cultural practices are to be developed.

5. In some parts of Salem and South Arcot Vallalar districts, cassava is grown in hilly

areas at an altitude of 500 masl. There is a need to develop varieties for these zones

along with agronomic practices.

6. Much emphasis is now given for production of organic foods. There is a need to

127

intensify research on organic gardening with special reference to the use of organic 8-

manure, biofertilizers and biocontrol of pests and diseases.

7. Crop improvement programs are therefore to be planned with the objective of

developing varieties with shorter crop duration (< 7 months), high root yield (> 35 t/ha),

high starch content in roots (>35%) and resistance to biotic (mosaic virus, root rot, tip

drying, leafspot and mites), and abiotic (drought and salt) stresses. Due emphasis is to

be given to developing crop production technologies suited to varied agroclimatic zones

of Tamil Nadu. It is also necessary to develop technologies for the manufacture of value-

added products utilizing cassava as the raw material.

8. The major reason for slow adoption rate of improved varieties is the lack of planting

material. There is a need for the development of large-scale rapid multiplication of elite

clones including in-vitro propagation.

9. It is estimated that 60% of the starch produced in India is from cassava roots and the

entire quantity is used for domestic consumption. At present the machinery used in the

sago and starch factories is old, which results in lower productivity and it takes a longer

time for extraction; these need to be modernized. Further, starch produced in these

factories do not reach the standards for export. The starch recovery is only 60% and

40% of the starch left in the fibrous waste material is used in cattle feed.

10. There exists the possibility of manufacturing starch and animal feed pellets for export

purpose. In Dharmapuri district, one fully-automated factory is being established for the

manufacture of starch, exclusively for export. A few factories have been set up for

manufacture of other value-added products, like industrial alcohol, sorbitol, liquid

glucose, dextrin, high-frutose syrup, glue, cattle feed etc. This is a good beginning.

There is need to develop varieties suitable for these various end-products and optimum

growing and processing technologies.

1 1 . The major constraint in the cassava industry is the high degree of price fluctuation,

both for fresh roots and for products like starch and sago (Figures 3 and 4). There is

a need to stabilize the market prices of roots and cassava-based products.

12. The starch and sago factories require a large quantity of water for starch extraction

and the effluent discharge pose a health hazard to the people and animals, as well as for

the environment. Hence there is a need to modernize factories and to develop new low-

cost effluent treatment technologies.

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REFERENCES

Anonymous. 1995. Horticultural Statistics. Departm. of Horticulture, Government of

Tamil Nadu. Madras, Tamil Nadu, India.

Ayyasamy, M. 1994. Irrigation scheduling for cassava comrade cropping system. PhD

thesis. Dept. Agronomy, TNAU, Tamil Nadu, India.

Mohammed Yassin. 1995. Studies on intercropping and nitrogen management in cassava.

PhD thesis. Dept. Agronomy, TNAU, Tamil Nadu, India.

Nanda, H.C., S.S. Rao and B.S. Chandrasekar. 1996. Stability analysis in short duration

cultivafs of cassava (Manihot esculenta Crantz). Indian J. Agric. Sc. 66(3): 165-169.

Nepolean, K. 1995. Studies on true seeds in cassava (Manihot esculenta Crantz) MSc

(Ag) thesis. Seed Technology, TNAU, Tamil Nadu, India.

Rajendran, P.G., S.G. Nair, C.S. Easwari Amma, K. Vasudevan and M.T. Shreekumari.

1993. Recent progress in cassava varietal improvement in India. In: R. Howeler

(Ed.). Cassava Breeding, Agronomy Research and Transfer of Technology. Proc. 4th

Regional Workshop, held in Trivandrum, Kerala, India. Nov. 2-6, 1993. pp. 61-83.

Susheela Thirumaran, A. and M. Aruna Seralathan. 1996. Process of cassava-based

defatted soy flower noodles suitable for school lunch programmes. Proc. 2nd Int.

Soybean Processing and Utilization Conference. Bangkok, Thailand. Jan 8-13, 1996.

pp. 257-261.

131

RECENT PROGRESS IN CASSAVA VARIETAL IMPROVEMENT

IN THE PHILIPPINES

Algerico M. Mariscal and Reynaldo V. Bergantin1

ABSTRACT

In recent years cassava has become an important raw material for various domestic needs

(food, feed, alcohol and high fructose sugar). To cope with high demand for cassava roots the

breeding and selection program has been intensified to identify varieties that are high yielding and

having high starch and dry matter contents. The continuous introduction of improved cassava

populations from the Thai-CIAT program and from CIAT/Colombia contributed to the

identification of good varieties, and, consequently, the establishment of cassava genepools having

a wide genetic base. This has led to the establishment of a breeding program using the best

parents of local and foreign sources.

Progress in selection for the last three years was observed but was not phenomenal. In

fact, from the regional trials jointly conducted by PRCRTC and its cooperating stations, two new

varieties of cassava from CIAT/Colombia selected by the University of the Philippines at Los

Banos, were released by the National Seed Industry Council. These are CM34 19-2A as PSB CV-

1 1 and SM972-20 as PSB CV-12. Both are intended for food and feed because of their low levels

of HCN.

Using the popular variety Lakan as check for the selection and evaluation among

introduced materials from CIAT/Colombia and Thailand, gradual progress is made in yield and

dry matter content. Superior varieties have been identified but are still in the pipeline for further

testing.

Varietal dissemination of new varieties has been intensified through on-farm trials and

demonstration farms in strategic areas where farmers have the opportunity to observe and select.

The involvement of the private sector, specifically the San Miguel Corporation, in the

creation of high demand for cassava has paved the way for the rapid increase of production in

terms of area and varietal dissemination.

For the last two years the Agribusiness Division of San Miguel Corporation has supported

3,000 ha of cassava in Mindanao. Support given is in terms of planting material, land preparation

and fertilizer input. All produce will go to San Miguel with a price profitable to the farmers.

The projected cassava area needed to meet the needs of San Miguel Corporation is 55,000 ha.

To this effect, variety trials are conducted in farmers. fields using recommended varieties (Rayong

60, Rayong 90, Rayong 5, KU-50 and the VC series) in Mindanao. Furthermore, rapid

propagation is planned to back-up the need for more planting material.

Aside from the San Miguel Corporation, starch millers throughout the country continue

to expand their production area due to the high demand for starch. High HCN varieties are

preferable. VC-5, which is high in HCN, is now planted in more than 3,000 ha in Lanao, while

more than 1,000 ha of Lakan are planted in Negros Occidental to support Unistarch.

Further selection will focus on identification of superior varieties with high starch content

and high yield while having low to high levels of HCN.

INTRODUCTION

In recent years, domestic utilization of cassava in the Philippines has markedly

increased. This is basically because cassava is recognized as a cheap raw material for

1 Cassava Breeders, Philippine Root Crop Research and Training Center (PRCRTC),

ViSCA, Baybay, Leyte, Philippines.

132

production of food, feed and other industrial products. This recent development has

finally realized the projection of the 1984 Asian Cassava Workshop in Thailand about the

future potential of cassava in Asia. In fact, Walters (1983), Lynam (1986) and Singh

(1986), emphasized that cassava will play a major role in satisfying the domestic needs

of the country and that any future increase in the output used by the cassava producing

countries in Asia should be aimed primarily at their domestic markets, such as for 1.

animal feed; 2. starch production (food processing, textiles, paper and board, modified

sugar); and 3. manufacture of ethanol.

True to the projection 12 years ago, cassava became an important raw material

for production of animal feeds, starch and its derivatives, as well as alcohol. The demand

for cassava roots is hastened by the involvement of the giant business conglomerate San

Miguel Corporation, which needs around 55,000 ha of cassava to supply their various

needs for feed, modified starch and alcohol (Bacusmo, personal communication). The

overall effect is the massive expansion of cassava production in terms of area and yield.

Superior varieties are, therefore, needed to satisfy the existing demand.

In support of this development, the cassava varietal improvement program of the

Philippine Root Crops Research and Training Center.(PRCRTC), and that at the Institute

of Plant Breeding (IPB) of the Univ. of the Philippines at Los Banos, will continue to

keep pace with the needs of the cassava industry. The introduction of elite materials from

the Thai-CIAT program and CIAT/Colombia has greatly improved the selection and

identification of best varieties for outright release and for utilization as cross parents in

the breeding program.

VARIETAL IMPROVEMENT

Breeding Objectives

The breeding objectives for cassava in the Philippines have not changed since

1987 (Mariscal and Bacusmo, 1995). Generally, the breeding activities aim to satisfy

the needs of the cassava farmers and processors who grow cassava in diverse agro-

climatic conditions and utilize the storage roots in a variety of ways. Specifically, the

breeding objectives are as follows:

1. High yield

2. High dry matter and starch content

3. Early harvestability

4. Resistance to pests and diseases

5. Tolerance to environmental stresses

6. Good plant type (root formation, root shape and branching habit)

7. Level of HCN (low for staple food, high for starch millers)

Recent Developments (1993-1996)

1. Germplasm collection

133

To back up the cassava improvement activities at PRCRTC, a germplasm

collection with wide genetic base is needed. Thus, PRCRTC maintained and upgraded

the genetic stocks of cassava. To date PRCRTC maintains in the field 300 cassava

accessions. These include 53 elite materials selected from Advanced Yield Trials as well

as from tissue culture materials introduced from Thailand (Table 1). With support from

the Cassava Biotechnology Network (CBN) of CIAT, germplasm materials from

PRCRTC will be sent to CIAT Headquarters in Colombia for global maintenance.

2. Advances in selection

Since the later part of 1993, 14,962 cassava hybrid seeds coming from 246

crosses were introduced to PRCRTC (Table 2). A total of 4,405 hybrid seedlings have

been evaluated. Most of these hybrid seedlings came from the seed introduction from

CIAT/Colombia and the Thai-CIAT program at Rayong. Summaries of the number of

genotypes at different testing stages are shown in Table 3. Since 1993, all trials

conducted included materials from both Thailand and Colombia, with Lakan, a variety

with a very stable yield and adaptability, used as check variety. From the replicated trials

of all entries from the Thai-CIAT program, specifically the MT series, there was no

progress in terms of yield and harvest index. However, it seems that there is positive

improvement in terms of dry matter content (Figure 1). This shows that the check

variety Lakan is actually quite good.

Table 1. Cassava germplasm collection at PRCRTC, ViSCA, Baybay, Leyte,

Philippines, 1993-1996.

Source 1993/94

No. of Accesions

1994/95 1995/96

Local 86 86

Foreign 131 131

Tissue culture (Thailand) 30 30

Elite clones 26 41

Total 273 288

86

131

30

53

300

134

Table 2. CIAT cassava hybrid seeds supplied to PRCRTC, ViSCA, Baybay, Leyte.

1993-1996.

Number of Number of

Date seeds crosses Sources

March 1993 2,361 35 CIAT/Colombia

June 1993 1,050 29 Thai-CIAT program

July 1994 1,250 26 Thai-CIAT program

July 1994 2,038 35 CIAT/Colombia

March 1995 2,043 35 CIAT/Colombia

May 1995 1,190 17 Thai-CIAT program

January 1996 2,230 31 CIAT/Colombia

April 1996 1,350 19 Thai-CIAT

program

July 1996 1,450 19 Thai-CIAT program

Total 14,962 246

Table 3. Number of entries in different stages of cassava selection by PRCRTC,

ViSCA, Baybay, Leyte, Philippines. 1993-1996.

Year

Selection stage 1993/94 1994/95 1995/96 Total

Observational Trial (Fl seedlings) 1,193 1,850 1,362 4,405

Single-row Trial 392 695 410 1,497

Preliminary Yield Trial 72 136 53 261

General Yield Trial 25 73 22 120

Advanced Yield Trial 19 20 23 62

Regional Trial 10 10 10 10

Varietal Release 2 1 1 4

Promotional Trial - - 2 2

On-farm Trial/Verification 4 5 5 14

Total 1,717 2,789 1,886 6,375

Considering the OMR series from Thailand, a similar trend as that of the MT

series was observed. Not much improvement was observed, except for dry matter

content, which was similar to that of the check (Figure 2). These results are also shown

135

in Tables 7 and 8. From the MT series, no entry was able to surpass the check variety

in terms of yield. Lakan had a yield of 38.0 t/ha, while the highest yield among entries

was only 34.5 t/ha (MT4-111). However, with respect to dry matter, several entries

surpassed the check. Some of these entries are MT4-52 and MT4-251 with dry matter

contents of 37.4 and 37.0%, respectively (Table 4). The check variety had only 34.0%

dry matter.

From the OMR series (Table 5) only one entry, CMR33-13-14, produced a high

yield of 60.4 t/ha, which surpassed the check. Nevertheless, many of the entries had high

dry matter contents that are comparable to, or far better, than that of the check variety.

These are CMR33-13-14, OMR33-12-3, OMR33-12-7 and OMR33-15-3 with dry matter

contents of 34.9, 35.8, 36.2 and 35.2%, respectively. Lakan had 34.9% dry matter.

Table 4. Yield parameters of six cassava hybrids from the Thai-CIAT program

evaluated in the Advanced Yield Trial conducted at PRCRTC in 1994/95.

Entry

Fresh root Dry matter Starch Harvest

yield content content index

(t/ha)" (%) (%)

MT12-44

MT4-111

MT4-52

MT9-21

19.0

34.5

23.7

26.5

34.6

32.9

37.4

33.2

22.5

20.2

26.4

20.6

0.46

0.56

0.46

0.62

MT4-251

MT 15-32

Lakan(check)

VC-4(check)

Average

14.6

26.5

38.0

25.2

24.1

37.0 25.8 0.59

35.9 24.4 0.50

34.0 21.7 0.55

31.1 17.6 0.60

35.2 23.3 0.52

" Average over 4 replications

Source: PRCRTC, 1995

E ^

c p

.2 £oJ o

a 3Q. i-

O U

°- §60

.S 6^

Lakan (Check)

92-93 93-94 94-95

Figure 1. Change ofmean frequency of all entries in Replicated Yield trials in terms of

fresh root yield, dry matter content and harvest index of materials

(MT series) from the Thai-CIATprogram.

s §3 O

o Sa- >

60 °

41*^ —-

<u

—

03

140-

130-

120.

110.

100

90

80

70

Lakan (Check)

root dry matter

harvest index

O

fresh root yield

-+- +

92-93 93-94 94-95

Figure 2. Change ofmean frequency of all entries in Replicated Yield Trials in terms of

fresh root yield, dry matter content and harvest index ofmaterials

(OMR series) from the Thai-CIATprogram.

137

Table 5. Yield parameters of eight cassava hybrids from the Thai-CIAT program

evaluated in the Advanced Yield Trial conducted at PRCRTC in 1994/95.

Fresh root Dry matter Harvest HCN

Entry yield

(t/ha)"

content

(%)

index rating21

CMR33-13-14 60.4 34.9 0.58 5

OMR33-12-3 38.5 35.8 0.55 6

OMR33-12-7 38.9 36.2 0.57 6

OMR33-11-7 40.8 32.9 0.59 5

OMR33-05-1 34.6 33.4 0.58 7

OMR33-15-3 26.6 35.2 0.42 6

OMR33-15-5 38.2 32.7 0.62 5

Rayong 60 47.9 32.7 0.62 8

VC-4(check) 46.6 31.1 0.62 4

Lakan(check) 53.8 34.9 0.68 4

Average 40.7 34.2 0.57

"Average over 4 replications

2lBased on picrate test rating scale of 1 to 9:1 =Iow, 9 = high

Source: PRCRTC, 1996

From all entries in the Replicated Yield Trials with materials from

CIAT/Colombia, no gain in selection was observed in terms of yield (Figure 3). The

same pattern was also observed among entries of tissue-culture derived materials (Figure

4). Table 6 clearly shows that only one entry, SM 1558-2, produced a higher yield of

31.4 t/ha than the check, which produced 29.3 t/ha. However, several entries had high

dry matter contents, which are comparable to, or even better than, that of the check. In

Table 7, MMal 2 produced the highest yield of 50 t/ha, which surpassed that of the

check cultivar. With respect to dry matter, no entry surpassed the check (Lakan).

These results clearly demonstrate that materials from the Thai-CIAT program and

from CIAT/Colombia have high dry matter contents. Though there have been remarkable

yield increases observed, superior clones/lines that could become candidates for varietal

release and subsequent use in production areas in the Philippines have still to be

identified.

138

Table 6. Yield parameters of 12 cassava hybrids from CIAT/Colombia evaluated in

the General Yield Trial at PRCRT in 1994/95.


Entry yield content

(%)

index rating21

(t/ha)1'

CM6149-3 20.3 34.8 0.60 5

CM6 149-5 15.0 33.9 0.52 5

SM 1449-9 19.1 33.5 0.61 3

SM1451-3 22.4 33.7 0.55 4

SM 1477-3 17.8 31.1 0.43 4

SM 1477-5 23.6 35.2 0.48 5

SM1542-5 10.3 33.2 0.62 5

SMI 544-1 15.6 33.7 0.46 3

SMI 558-2 31.4 34.9 0.56 3

SM 1558-9 20.3 31.2 0.58 5

SMI 564-8 14.9 37.6 0.44 3

SM 1565-1 17.3 39.7 0.45 4

Lakan(check) 29.3 34.8 0.57 3

VC-1 (check) 21.5 34.7 0.58 4

VC-3(check) 31.3 32.1 0.62 3

Average 16.4 34.4 0.52

"Average of 3 replications

2,Based on picrate test rating scale of 1 to 9: 1 =low, 9=high

Source: PRCRTC, 1996.

139

coo

u

>o

u

s

5c

m

140-

130

120

110

100

90

80

70

Lakan (Check)

~• root dry matter

~~A harvest index

fresh root yield

93-94 94-95 95-96


fresh root yield, dry matter content and harvest index of materialsfrom

CIAT/Colombia.

a120o

o

> 110c

£ 100

Su 90B

1 80

70

harvest index

93-94 94-95 95-96


fresh root yield, dry matter content and harvest index oftissue culture-

derived materialsfrom CIAT/Colombia.

140

Table 7. Yield parameters of ten cassava hybrids from the Thai-CIAT program

introduced through tissue culture, and evaluated in the Advanced Yield

Trial at PRCRTC in 1994/95.

Fresh root Dry matter Starch Harvest

Entry yield content content index

(t/ha)" (%) (%)

CM3299-4 29.2 36.1 24.5 0.38

CM4054-40 24.7 36.5 25.1 0.60

MCol 2215 23.5 37.2 26.1 0.56

CM2772-3 27.3 37.4 26.4 0.52

Rayong 60 36.8 36.5 24.2 0.63

CM4231-32 28.3 32.9 20.1 0.58

CM3306-4 25.8 38.2 27.5 0.48

MCol 1505 33.8 36.5 25.2 0.48

MMal 2 50.0 35.5 23.7 0.46

CMR29-56-101 15.4 33.7 21.2 0.49

Lakan(check) 36.5 38.4 27.8 0.49

VC-4(check) 40.8 34.9 22.9 0.62

Average 29.5 36.0 24.5 0.56



3. Utilization of CIAT germplasm for local hybridization

Aside from screening and field evaluation of introduced hybrid seeds from CIAT,

the PRCRTC utilized elite clones for its hybridization work to improve the local

cultivars. A hybridization block was established and selected parents of local and foreign

origin were planted for subsequent crossing. Open pollinated seeds in the germplasm

collections were gathered for possible screening and evaluation. Controlled crossing work

is still to be undertaken upon flowering of parental lines.

From the hybrid population previously developed, five promising local hybrids

are included in the Regional Trial. Potential varieties for recommendation are the

following: CMP62-15 and CMP21-15, each with average yields of 24.0 t/ha (Table 8).

These two possible varieties outyielded the two check varieties.

141

Table 8. Average cassava root yields (t/ha) in Regional Trials conducted in eight

locations in the Philippines from 1990 to 1995/96.

Year

General

averageEntry 1990-93 1993/94 1994/95 1995/96

1. CMP21-6 . 17.5 25.3 - 21.4

2. CMP62-15 - 20.6 22.4 20.3 24.0

3. CMP32-10 - 14.9 31.2 19.2 21.8

4. CMP26-1 - 21.3 22.7 - 22.0

5. CMP21-15 - 24.9 26.1 21.0 24.0

6. VC-2(check) 26.4 17.7 26.1 17.8 22.0

7. CM3419-2A** 27.4 19.7 24.9 - 24.0

8. CM3283-4 24.8 14.5 21.8 - 20.4

9. CM3422-1 25.9 12.6 25.4 28.9 23.2

10. SM928-1 - 20.3 19.9 25.0 21.7

11. SM972-20** - 13.6 39.1 24.1 25.6

12. UPLCa-5(check) - 14.6 19.9 19.7 18.1

13. SM577-8* - - - 16.2 16.2

14. SM466-6* - - - 32.3 32.3

15. CG90-4-1* - - - 32.4 32.4

16. CG87-3-11* - - - 29.0 29.0

** Approved by the National Seed Industry Council for release

* New entry for Regional Trial

4. Evaluation for tolerance to shade and red spider mites

Considering that large areas intended for cassava in Mindanao and the Visayas

are presently under coconut, selection of cassava genotypes grown under this condition

was undertaken to identify cassava genotypes that will tolerate partial shading. Results

of the General Yield Yrial involving the introduced materials from the Thai-CIAT

program are very promising (Table 9). Several hybrids had a superior performance under

coconut compared to the check variety Lakan. Some of the superior clones are CMR33-

13-11, OMR33-12-3, OMR33-12-7 and OMR33-05-2 having average yields of 24.2,

20. 1 , 20.0 and 17. 1 t/ha, respectively. Aside from yield, the CIAT materials have high

dry matter contents that are comparable and even higher than that of the check variety.

It is expected that from this population improved and superior genotypes suited for

growing under coconut will be identified.

The screening for tolerance to red spider mites involving locally developed

hybrids tested in the Advanced Yield Trial has resulted in the identification of two clones

that outyielded the check variety (Table 10). These clones are MOP24-2-13 and

MOP24-2-40 with average yields of 12.5 and 12.7 t/ha, respectively. Generally, all

142

selections have shown field resistance to mites. However, the yields obtained were not

high because the plants were affected by a strong typhoon during their critical growth

period. Several trials, both for shade and mite tolerance, are still on-going.

5. Varietal release

Regional trials conducted during the period 1993-1996 have resulted in the release

of two new cassava varieties by the National Seed Industry Council (NSIC), formerly

known as the Philippine Seed Board (PSB). The two varieties of CIAT origin are

CM3419-2A released as PSB CV-1 1, and SM972-20 released as PSB CV-12. These two

new varieties were selected by the breeding program of the Institute of Plant Breeding

at the University of the Philippines at Los Bafios from the materials introduced from

CIAT/Colombia. Both varieties have a low level of HCN and can be used both for

human food and feed. Tables 8, II and 12 show the performance of these cultivars in

the Regional Trial.

It is interesting to note that some progress has been made in the selection for high

yield among high HCN entries. However, the selection for high dry matter content

among these high HCN varieties has not yet produced positive results (Figure 5). On the

other hand, for low HCN entries (such as the two released varieties), remarkable results

have been obtained in the selection for high yield, and some progress has been made in

selecting for high dry matter content (Figure 6).

6. Varietal dissemination

Nowadays, the quest for planting materials of high-yielding cassava varieties

continues to rise. Expansion of production areas in Mindanao, specifically in Lanao and

Bukidnon provinces is the outcome of the San Miguel Corporation.s Agribusiness

Divisions' campaign for production of cassava to satisfy their current demand. No less

than 55,000 ha are needed by San Miguel to supply their needs for production of animal

feeds, modified starch and alcohol. For the last two years, this company has supported

3,000 ha of cassava. Support given was in terms of planting material, land preparation

and fertilizer inputs. Farmers are made to sign a contract with San Miguel stipulating

that all their produce will be absorbed by the company at an assured market price.

Lately San Miguel is buying cassava dried chips at P2.50 per kilo. For initial expansion,

the readily available Golden Yellow variety was used by the farmers.

The need for cassava raw materials was also felt by the starch processors and other feed

millers in Mindanao. As such, cassava became a high demand commodity.

143

Table 9. Yield parameters of ten cassava hybrids from the Thai-CIAT program

evaluated in a General Yield Trial under coconut at PRCRTC in 1994/95.


Entry yield

(t/ha)"

content index rating2'

CMR33-13-8 9.3 34.3 0.48 6

CMR33-13-10 13.8 31.7 0.53 6

CMR33-13-11 24.2 35.8 0.54 7

CMR33-13-14 14.3 34.5 0.52 5

OMR33-12-3 20.1 36.6 0.61 7

OMR33-12-7 20.0 37.4 0.60 6

OMR33-11-7 15.3 34.8 0.66 6

OMR33-62-9 14.1 34.9 0.63 6

OMR33-05-1 16.2 36.2 0.62 6

OMR33-05-2 17.1 35.8 0.60 7

Lakan(check) 16.3 35.8 0.49 5

VC-3(check) 16.4 32.6 0.54 6

Average 16.4 35.2 0.58


:.Based on picrate test rating scale of 1 to 9: 1 = low, 9 = high


144

cz

—U>

-J

£

140

130

120

110

100

90

80

70

+

93-94

fresh root yield

UPL Ca-5 (Control)

root dry matter

+ +

94-95 95-96

Figure 5. Change in mean frequency of all entries in Regional Yield Trials in terms of

root yield and dry matter content of high-HCN cassava accessions.

fresh root yield

=z■->

t_

>z

%J

£

c

UJ

93-94 94-95 95-96

Figure 6. Change in mean frequency of all entries in Regional Yield Trials in terms of

fresh root yield and dry matter content oflow-HCN cassava accessions.

145

Table 10. Yield parameters of seven locally developed hybrids for mite resistance

evaluated in the Advanced Yield Trial at PRCRTC in 1995/96.

Fresh root Dry matter Harvest Mite

Entry yield

(t/ha)"

content

(%)

index reaction2'

MOP24-2-34 9.3 36.2 0.42 R

MOP24-2-13 12.5 35.1 0.37 R

MOP24-2-19 9.0 35.1 0.42 R

MOP24-2-40 12.7 32.7 0.45 R

MOP24-2-8 7.4 39.4 0.48 R

MOP24-2-46 7.2 32.5 0.38 R

MOP24-2-4 8.4 38.1 0.49 R

Lakan(Check) 12.4 39.6 0.49 R

Avarage 9.8 35.6 0.38


^R means resistant

Source: PRCRTC 1996

As far as varietal preference is concerned, feed millers prefer low-HCN varieties,

while starch millers prefer high-HCN varieties. In effect, VC-5, which has high HCN

is now planted in more than 3,000 ha in Lanao for starch production. Lakan, on the

other hand, is now planted in more than 1,000 ha in Negros Occidental for starch

production by Unistarch. Similarly, Lakan is also widely grown in Bohol to support

Philstarch. With this development, farmers clamor for planting material of new high-

yielding varieties. In their support, PRCRTC has undertaken several activities as

follows:

Promotional trials

These trials are conducted in areas where cassava is a dominant crop. Farmers

like to see for themselves the performance of new varieties before adopting them. Thus,

promotional trials enable farmers to select which varieties they wish to plant.

A farmer in southern Leyte who supports a cooperative cassava-based feedmill-

project participated in a promotional trial, which was established using four recommended

varieties planted on big plots on sloping land. Vetiver grass was planted as contour

hedgerows to reduce erosion. Results of the trial, which was jointly observed by farmers

146

and researchers, were quite good (Table 13). VC-1 gave the highest yield of 34.0 t/ha.

Farmers liked all of the varieties tested. In fact, all stakes were subsequently planted,

resulting in a 40 ha expansion for the varieties tested. Presently, an On-farm Trial

including several varieties is being conducted at Baloi, Lanao del Norte in cooperation

with San Miguel Corporation. The varieties planted are: Rayong 60, Rayong 90, Rayong

5, KU-50, VC-1, VC-2, VC-3, VC-4, VC-5 and Lakan.

Establishment (4 Model Farms and Nurseries

To facilitate further distribution of new cassava varieties, PRCRTC initiated the

establishment of one-hectare model farms in strategic locations in Mindanao where the

bulk of cassava production is located. The model farms all intended to showcase the

recommended varieties plus the necessary cultural management practices. These will also

serve as the source of planting material for the farmers in the area. One model farm in

Bukidnon, which was jointly supported by PRCRTC and San Miguel Corporation,

produced yields of 40 t/ha.

Table 11. Summary data of the newly released cassava line CM 3419-2 and the check

variety VC-2"

Parameters CM3419-2 as PSB CV-1 1 Check VC-2

25.0

32.1

19.0

low

MR

HR

HR

"Average over 14 trials in 6 locations, 1991-1995.

Average fresh root yield (t/ha) 25.5

Dry matter content(%) 30.2

Starch content(%) 16.4

HCN content low

Reaction to pests and diseases:

a. Red spider mite HR

b. CBB HR

c. Scale insects HR

147

Table 12. Summary data of the newly released cassava line SM 972-20 and the check

variety VC-2"

Parameters

Average fresh root yield (t/ha)

Dry matter content(%)

Starch content(%)

HCN content

Reaction to pests and diseases:

a. Red spider mite

b. CBB

c. Scale insects

"Average over 11 trials in 6 locations, 1993-1996.

SM972-20as Check

PSBCV-12 VC-2

23.0 21.4

33.9 32.1

21.5 19.6

low low

HR MR

HR HR

MR HR

Table 13. Resuls" of On-farm Trial of four cassava varieties planted on sloping land

in Bontoc, southern Leyte, Philippines, in 1993/94.

Fresh root Dry matter HCN

Entry yield (t/ha) content (%)rating2>

VC-1 34.0 33.26

VC-2 19.6 30.33

VC-3 25.6 27.03

Lakan 26.1 34.32

Average 26.3 31.2

"Average over 4 replications, plot size 60 sq. meters

2>Based on picrate test rating scale of 1 to 9 : 1 =low, 9 = high


148

Aside from the model farms, nurseries of the new cassava varieties are initiated

under the management of farmers cooperatives. Planting material produced will be

distributed to other farmers at cost.

Considering the urgency of the need for more planting material of improved

varieties, the Agribusiness Division of San Miguel Corporation will adapt a rapid-

propagation technique for multiplication of varieties supplied by PRCRTC. In this way

a more rapid dissemination of new cassava varieties can be attained.

FUTURE PLANS

With the expansion of the area planted to cassava, PRCRTC will have to double

its efforts to monitor the performance of cassava varieties planted in these plantations.

The Center will also conduct intensive selection for superior varieties for the food, feed

and alcohol industry.

The competitive advantage of cassava over other crops as raw material for

domestic utilization is very high. Thus, in line with the Medium-Term Philippine

Development Plan, priorities are geared toward domestic utilization of cassava.

PRCRTC will cooperate in the effective transfer of mature technologies to cassava

farmers and processors.

It is envisioned that in the next five years, average yields will increase and

dissemination and adoption of new recommended varieties will have markedly increased.

Accordingly, the breeding objectives for cassava will remain the same, but more

emphasis will be on the identification of superior varieties with high yield, high starch

content and low to high HCN levels that will suit the various needs of the food, feed,

flour and starch industries.

For effective technology transfer, closer cooperation among the government

institutes, non-government organizations (NGOs) and the private sector will be sought.

REFERENCES

Lynam, J.K. 1986. A comparative analysis of cassava production and utilization in tropical

Asia. In: Future Potential of Cassava in Asia. Proc. of Regional Workshop, held in Bangkok,

Thailand. June 4-8, 1984. pp. 171-196.

Mariscal, A.M. and J.L. Bacusmo. 1995. Recent progress in cassava varietal improvement

in the Philippines. In: R.H. Howeler (Ed.). Cassava Breeding, Agronomy Research and

Technology Transfer in Asia. Proc. 4th Regional Workshop, held in Trivandum, Kerala,

India. Nov 2-6, 1993. pp. 306-321.

Shingh, R.B. 1986. Past performance and future prospects of cassava products in Asia and the

Pacific Region. In: Future Potential of Cassava in Asia. Proc. of Regional Workshop, held in

Bangkok, Thailand. June 4-8, 1984. p. 404.

Walters, P.R. 1983. Cassava's markets - where next? World Crops, pp. 130-133.

149

RECENT PROGRESS IN CASSAVA VARIETAL IMPROVEMENT IN

INDONESIA

Soemarjo Poespodarsono1

ABSTRACT

In Indonesia, cassava is used mostly for human consumption, while a smaller part is used

for animal feed and as raw material in industry. This crop is cultivated in almost all provinces

of Indonesia. However, because the amount of rainfall among the regions varies and is not evenly

distributed, some regions have a wet climate while others have a dry climate. The type of climate

affects the suitability of a particular variety and its productivity.

The area planted to cassava in Indonesia is about 1.3 million ha producing approximately

16.3 million tons fresh cassava roots; this means that the average production per hectare is still

low at about 12.2 t/ha. This low yield is due to the use of local varieties, traditional cropping

patterns and simple cultural practices. According to the government, cassava production is

projected to increase to about 16.5 million tons in the year 2000. This production can be achieved

by intensifying the cultural practices as well as by the use of higher yielding cassava varieties,

either sweet or bitter ones.

Up to now, a very limited number of high yielding varieties have been released, i.e. only

ten new varieties from 1969 to 1990 for all cassava areas in Indonesia, compared to 74 rice, 28

maize, 25 soybean, and 5 sweet potato varieties. Some new cassava varieties were released, such

as Adira 1 (sweet) and Adira 2 (bitter) in 1978, and Adira 4 (bitter) in 1986. In 1993 MARIF

(Malang Research Institute for Food Crops) released two new varieties named Malang 1

(CM4049-2) and Malang 2 (CM4031-10).

Since 1984, Brawijaya University, in cooperation with CIAT, has been conducting cassava

breeding. From F, cassava seed that had been provided, four promising clones were selected, i.e.

UB 1/2 (CM3962-2), UB 15/10 (CM3380-10), UB 881-5 (SM881-5) and UB477-2 (SM477-2).

Multi-location trials have been conducted several times with these clones, especially in East Java.

Concerning governmental regulations about the realease of new varieties, one must conduct multi-

locational trials of these promising lines or clones in at least five provinces. In 1995, those

promising cassava clones were planted in East Java, Central Java, Lampung, North Sulawesi and

Lombok. The result of these trials could suggest the release of these lines as new cassava

varieties. From the results it was concluded that clones UB 1/2 and UB 15/10 (both bitter) are

more suitable for regions with a wet climate, while clones UB 881-5 (bitter) and UB 477-2 (sweet)

are more suitable for those with a dry climate.

INTRODUCTION

In Indonesia, cassava is cultivated in almost all provinces, particularly by small

farmers but also by some large plantations. Recently, the cassava area has been

approximately 1.33 million hectares, producing 16.3 million tons of fresh roots with an

average yield of 12.2 t/ha (CBS, 1992). Most cassava produced by small farmers is used

for food, either as occasional dishes or as a staple food; the rest is processed into dried

root pieces (gaplek) or into starch. Cassava produced by big farmers or plantations is

processed almost entirely into starch. Due to the usage of cassava roots mainly as human

food, sweet varieties are needed for food or starch production, while bitter varieties can

Brawijaya University, Malang, E. Java, Indonesia.

150

be used for production of dried roots, starch or animal feed. In general, cassava has a

low social status, which is a factor that affects the price and government policy.

According to government planning, the projected increase in cassava production during

the next five years is only 0.17% per year, compared with 2.01% for rice, 3.77% for

maize, 3.17% for soybean and 1.96 for sweet potato (NBP, 1993).

Cassava is planted in various types of soils and climates. Generally, the planting

area of cassava consists of uplands, while a few areas are marginal land. As a result,

cassava productivity and planting time depend on rainfall and its distribution. Based on

Oldeman's climatic classification, climate types A up to type E are found in Indonesia.

According to these climate types, Indonesia is generally divided into two main regions:

one having a wet climate (A and B types) and another having a dry climate (C, D and

E types). Roughly, the wet climate is found in the western and northern part and the dry

climate in the southeastern part of Indonesia, including most of East Java. In the wet

region cassava can be planted at any time of the year, but this is not the case in the drier

regions, where cassava is planted at the beginning of the wet season. This affects the

availability of cassava roots as raw material for the starch industry. Since cassava can

be planted throughout the year in Sumatra most of the large cassava plantations are found

there. Rainfall distribution also determines the yield of cassava (Wargiono, 1990).

Up to now farmers still plant many local varieties. These varieties are well

adapted to the local environment, but they generally have a low starch content. On the

other hand, a limited number of high-yielding varieties have been released, but not all

of these were distributed to farmers. From 1969 to 1993 only ten new cassava varieties

have been released, compared with 74 varieties of rice, 28 of maize, 21 of soybean and

5 of sweet potato (Baihaki, 1996). Two cassava varieties, i.e. Adira 1 (sweet) and Adira

2 (bitter), were released in 1978. Adira 4 (another bitter variety) was released in 1986

and is now widely grown. In 1993, MARIF (Malang Research Institute for Food Crops),

now renamed as RILET (Research Institute for Legumes and Tuber Crops) released

another two varieties, i.e. Malang 1 (CM4049-2) and Malang 2 (CM4O31-10).

Considering that a wide range of ecological conditions exist in Indonesia, there

is a need for many high-yielding varieties that are adapted to special local environments.

That is why Indonesia needs more than one institution for handling the cassava breeding

program.

CASSAVA BREEDING IN INDONESIA

Cassava breeding and the release of new varieties dates back to Dutch colonial

times. During that era, some high-yielding varieties were probably released since many

local varieties still have Dutch names, such as Faroka and Vandrum. These varieties,

as well as others released at that time, are bitter varieties and were cultivated in areas

surrounding starch factories. Sweet varieties were planted mainly near the farmers'

homes.

151

Since 1984, Brawijaya University has been involved in cassava breeding, along

with the Research Institutes for Food Crops in Bogor and Malang, and in close

collaboration with CIAT. At the same time, CIAT also cooperated with private

institutions such as the Umas Jaya Farm, which is located in Lampung province of

Sumatra. Thus, cassava breeding is conducted in the two main regions, namely the wet

region, represented by Bogor (West Java) and the Umas Jaya Farm, and the dry region,

represented by Malang in East Java. It is expected that several high-yielding varieties

will be released in the future, with each one adapted to a given environment.

The main objective of the cassava breeding program in Indonesia is to produce

both sweet and bitter cassava varieties with the following characteristics:

1. High root yield

2. High harvest index

3. High root starch content

4. Tolerance to major pests and diseases

5. Non-branching growth habit

6. Good root shape

High root yield has the highest priority. Because many farmers are using high

inputs, so they expect a variety to respond well to fertilizers and to good management.

A high harvest index is needed in order to minimize total nutrient uptake and prevent

nutrient exhaustion of poor upland soils. Varieties with high root starch content are

preferred by farmers and cassava plantations, because the price of cassava is calculated

from its starch content. Since most farmers do not control pests and diseases they need

varieties that are tolerant to the major pests and diseases. A non-branching growth habit

is preferred by farmers, because cassava is often intercropped with other annual crops;

non-branching varieties cause less competition to those intercrops. The last

characteristic, i.e. good root shape, is of particular interest to large cassava plantations,

because it facilitates the harvest.

Besides the general objectives mentioned above, there are also more specific

objectives which aim to solve various adverse conditions. The specific objectives are:

1. Tolerance to certain adverse soil and climatic conditions

2. Early harvestability

As mentioned before, cassava is mainly planted in uplands having different soil

and climatic conditions, including some adverse conditions, such as long dry seasons or

high levels of soil acidity; so, in order to obtain relatively high yields, varieties well

adapted to those conditions are needed. A variety with early harvestability aims to spread

the time of harvest, particularly to allow small farmers to increase their income.

Breeding Activities

Cassava breeding activities at Brawijaya University start with single plant

152

selections from F, seeds. Initially these seeds were introduced only from

CIAT/Colombia and about 2,000-3,000 seeds were sent each year. Since 1993/94,

however, also F, seeds from the Thai-CIAT program, with clone codes of OMR or

CMR, have been received.

At the start, each seed is germinated in polybags and after 2-3 months the

seedling are transplanted to the experimental field. At harvest time about 10-20% of

plants are selected, based on root size and shape as well as other morphological

characteristics. The second generation is planted in a Single Row Trial with stakes from

each selected clone, generally five stakes for one row of each line and with two rows of

control varieties, i.e. Adira 4 (a national high-yielding variety) and Faroka (a local

variety). These two control varieties are used for all stages of selection. The selection

criterion for this second step is that selected clones must yield higher than or equal to the

control varieties. This criterion is similar to that used in the third generation, i.e. the

Unreplicated Yield Trial, in which each line is planted in a single plot. The next

selection step is called the Advanced Yield Trial, which uses a randomized block design

with three replications. In this generation, usually 15-20 clones are selected. Fresh root

yield, root dry matter content (RDMC), biomass and harvest index are determined at

harvest time. Usually, from these trials, sufficient planting material is obtained for

planting in three sites of the Multi-location Trial.

In this paper, the results of these Multi-location Trials, conducted in Jatikerto

(Central Malang), in Kalipare (South Malang) and in Tarokan (Kediri), are presented in

Tables 1, 2 and 3, respectively. All these sites are located in East Java.

Table 1. Results of a Multi-location Trial conducted at Jatikerto Experiment Station

in Malang, East Java, Indonesia in 1994/95.

Total Harvest

Fresh root RDMC biomass index

Clones Parents yield (t/ha) (%) (t/ha)

OMR33-05-4 CMC76 37.2 33.1 46.7 0.80

OMR33-10-3 Rayong 5 30.0 34.8 50.7 0.54

OMR33-10-8 Rayong 5 33.0 34.8 57.7 0.57

CMR33-56-5 - 27.4 35.7 41.6 0.65

OMR33-10-11 Rayong 5 37.0 32.4 56.7 0.65

CMR33-12-14 CMR26-14-9xR90 30.3 34.0 46.3 0.65

CMR33-52-9 CMR26-14-9xR90 29.8 35.5 38.8 0.77

CMR33-56-8 CMR26-14-9)cR90 25.7 34.4 34.3 0.75

CMR33-52-8 CMR26-11-9)cR90 21.3 34.7 30.2 0.71

Adira 4(control) 25.4 34.0 38.6 0.66

Faroka (control) 34.6 33.6 49.1 0.70

153

Table 2. Results of a Multi-location Trial conducted in Kali pa re in South Malang,

East Java, Indonesia in 1994/95.

Total Harvest

Fresh root RDMC" biomass index


OMR33-05-4 CMC76 24.0 33.5 36.8 0.65

OMR33-10-3 Rayong 5 24.9 33.4 36.7 0.68

OMR33-10-8 Rayong 5 23.1 32.6 36.3 0.64

CMR33-56-5 - 21.5 35.6 32.8 0.66

OMR33-10-11 Rayong 5 25.5 32.1 36.6 0.64

CMR33-12-14 CMR26-14-9xR90 20.5 34.7 31.7 0.65

CMR33-52-9 CMR26-14-9xR90 20.1 34.9 30.9 0.65

CMR33-56-8 CMR26-14-9xR90 30.7 35.0 33.0 0.63

CMR33-52-8 CMR26-1l-9xR90 19.2 34.5 29.0 0.66

Adira 4(controi;1 24.4 35.7 38.5 0.63

RDMC = root dry matter content

Table 3. Results of a Multi-location Trial conducted at Tarokan in Kedire,

Java, Indonesia in 1994/95.

East

Total Harvest

Fresh root RDMC" biomass index


OMR33-05-4 CMC76 23.5 32.6 34.1 0.69

OMR33-10-3 Rayong 5 24.1 31.3 33.9 0.71

OMR33-10-8 Rayong 5 24.1 31.2 37.4 0.64

CMR33-56-5 - 19.8 35.0 29.8 0.66

OMR33-10-11 Rayong 5 21.2 31.4 33.5 0.63

CMR33-12-14 CMR26-14-9xR90 18.9 34.5 28.1 0.67

CMR33-52-9 CMR26-14-9xR90 17.7 34.9 26.0 0.68

CMR33-56-8 CMR26-14-9xR90 15.1 35.2 22.0 0.69

CMR33-52-8 CMR26-1l-9xR90 13.2 34.8 21.1 0.66

Adira 4(controi;1 25.3 34.8 37.7 0.67

" RDMC = root dry matter content

Among these three locations, the soil and rainfall conditions of Jatikerto are

better than those of Kalipare and Tarokan. This affects the performance of the selected

clones. From these tables it is clear that OMR33-05-4 produced a high root yield and

154

had a relatively high RDMC and harvest index. But OMR33-10-3 seems to be more

suitable for poor conditions, such as in Kalipare and Tarokan.

Similar previous trials have produced several highly promising clones, such as

UB 1/2 (CM3962-2, a selection from a cross of MCol 22 with CM849-1), UB 15/10

(CM3380-10, a selection from a cross of CM568-1 with CM523-7), UB 881-5 (SM881-5,

selected from open-pollinated seeds of CM849-1) and UB 477-2 (SM479-2, selected from

open-pollinated seeds of CM 1022-4). According to government regulations, promising

lines or clones can be released as new varieties only if they have been tested in at least

five provinces (Multi-provincial Trials). Therefore, these highly promising clones have

also been tested for this purpose in Lampung (Sumatra), Central Java, East Java, North

Sulawesi, and Lombok. These trials have been harvested in early 1996, the result of

which are presented in Table 4. It seems that UB 1/2 (CM3962-2) and UB 15/10

(CM3380-10) produced high fresh root yields in most sites. In Central Java all clones

had relatively low yields, because cassava was intercropped with rice and maize, followed

by mungbean. From these results, the two promising clones, UB 1/2 and UB 15/10, will

be suggested to the Indonesian government for release as new cassava varieties.

Table 4. Results of Multi-provincial Trials conducted in Lampung, Central Java, East Java,

Lombok and North Sulawesi in 1995/96.


Clones Lampung Central

Java

East

Java

Lombok North

Sulawesi

Average

UB 1/2 33.3 22.6 23.7 37.5 46.2 32.7

UB 15/10 32.9 25.5 31.8 34.0 25.5 29.9

Kasetsart 50 31.9 - - - - -

UB 477-2 20.9 22.8 27.6 33.6 34.0 27.8

UB 881-5 18.0 21.4 29.1 29.6 29.5 25.5

UB 1-2/15 - 23.3 - 20.5 20.9 21.6

UB 1-2/20 24.6 - 32.1 31.4 32.7 30.2

CMR33-10/3 28.3 - - - - •

OMR30-10-11 - - 19.9 - - -

Adira 1 . 17.2 - . 21.1 19.1

Adira 4 29.9 - 25.6 23.1 22.1 25.2

Malang 1 23.5 21.8 28.3 23.2 22.9 23.9

Malang 2 - - - 25.1 24.5 24.8

155

REFERENCES

Baihaki, A. 1996. Prospek penerapan breeder right di Indonesia. Simposium Pemuliaan Tanaman

IV. PERIPI Komda, Jawa Timur. 16 p.

Central Bureau of Statistics (CBS). 1992. Indonesian Statistics.

National Bureau of Planning (NBP). 1993. Five Years of Indonesian Planning.

Poespodarsono, S. and Y. Widodo. 1995. Recent progress in cassava varietal improvement in

Indonesia. In: R.H. Howeler (Ed.). Cassava Breeding, Agronomy Research and Technology

Transfer in Asia. Proc. 4th Regional Workshop, held in Trivandrum, Kerala, India. Nov 2-6,

1993. pp. 175-182.

Wargiono J., 1990. Pengaruh distribusi curah hujan terhadap penampian klon ubikayu (Effect of

rainfall distribution on cassava performance). Penelitian Pertanian. Balai Penelitian Tanaman

Pangan. Bogor, Indonesia. No 10, Vol I:

156

CASSAVA VARIETAL IMPROVEMENT PROGRAM AT UMAS JAYA FARM

AND ITS CONTRIBUTION TO SMALL FARMER COMMUNITIES

IN SUMATRA, INDONESIA

Palupi Puspitorini1, Usman Kartawijaya1 and Kazuo Kawano2

ABSTRACT

A three-way collaboration in cassava varietal improvement and dissemination was

established in 1982, in which a development-oriented private corporation (Umas Jaya Farm in

Lampung, Sumatra of Great Giant Pineapple Coy of Gunung Sewu Group) provided ample

facilities for varietal selection, multiplication and dissemination to a resource-limited national

cassava breeding program (CRIFC), while an international organization (CIAT) contributed the

basic training of research personnel and additional breeding materials. The program continued

even after the CRIFC breeder left for abroad in 1989. This program is now regarded to be the

best functioning cassava varietal development program in Indonesia. We selected a clone with

distinctly high yield and root starch content from the original CRIFC breeding stocks, multiplied

it and released it. We donated the planting stakes of this cultivar to many small farmers.

cooperatives and shipped out millions of stakes to large plantations in and outside Sumatra. This

new clone is now widely known as M-31 in the production fields and Adira 4 in the official

registration. The economic benefit generated by the new cultivar started with the additional root

harvests and additional starch produced within UJF, but it soon spread into the production fields

of thousands of small farmers. Hard data, and a few extrapolations from these, indicate that Adira

4 is now planted in more than 100,000 ha and the additional economic effects caused by its

adoption is more than 194 million US dollars, of which at least one half has directly entered the

household income of innumerable small farmers.

We continued selections based on CIAT materials and are identifying new clones that are

better than Adira 4. From this work, two new cultivars, Malang 1 and Malang 2, were officially

released recently and one clone, Kasetsart 50, is being pre-released. Our collaborative program

offers an example that the private sector can efficiently and effectively handle cassava varietal

development, especially the multiplication and dissemination, when government research and

extension institutions cannot afford a functional research and dissemination program.

INTRODUCTION

Cassava has been a traditional food crop in the upland farming areas of Indonesia

and its role, especially as a famine relief crop, should not be underestimated. Yet, with

the continuous improvement of the diet of the rural population, especially through the

increased availability of rice, the form of cassava utilization has been shifting steadily

from fresh human consumption to processed foods, animal feed and industrial starch.

While the importance of cassava for direct human consumption is gradually decreasing,

its role as a major source of cash income for small farmers and as raw material for agro-

industry is rapidly increasing. Several large-scale cassava starch processing plants have

been established in southern Sumatra province of Lampung during the past fifteen years,

in order to supply starch to the national food industry utilizing existing small farmers'

1 Umas Jaya Farm, Great Giant Pineapple Coy, Lampung, Indonesia.

2 CIAT Asian Cassava Program, Dept. of Agriculture, Chatuchak, Bangkok, Thailand.

157

production, as well as that of the large areas of previously under-utilized land now used

for cassava plantations.

This is in accordance with the national policy of establishing agro-industries and

creating employment using under-utilized lands on the outer islands. Umas Jaya Farm

(UJF) was a pioneer of such enterprises, starting as a cassava production and starch

processing plantation. We established a collaborative cassava varietal development

program at UJF in 1982 and the initial development was highly successful. At the 3rd

Asian Cassava Research Workshop in 1990, we reported this initial success and

concluded the presentation by stating "How much of this success is going to be extended

to the mass of small farm communities is yet to be seen" (Hardono et al., 1992). Six

years later, we therefore report how the initial technical success has been transferred and

spread into the multitude of small farmers in Sumatra of Indonesia.

Umas Jaya Farm

A license to lease 13,000 ha of underutilized land located at Terbanggi Besar,

Lampung, Sumatra, was conceded by the Indonesian government to the Gunung Sewu

Group with the condition of developing the area for value-added agro-industrial

production. Cassava roots produced in their plantation and the starch processed from

these in their own factory were the major activities during the early years. The major

operation has gradually shifted to the production and canning of pineapple, which proved

to be more profitable for UJF. The pineapple operation, called Great Giant Pineapple

Company, now employs more than 10,000 workers.

The UJF planted cassava annually at their own plantation in areas between 0 and

3,000 ha during the past 15 years; presently, it is no longer planting cassava within the

UJF plantation, as the company has moved cassava production to their new satellite

operations outside UJF. The starch processing plant of UJF, which was processing only

the cassava roots produced in UJF in the early years, is now processing roots that are

nearly 100% produced by small farmers outside UJF. The capacity of the starch factory

is being upgraded to absorb more cassava produced by small farmers outside.

Thus, the production of fresh cassava roots has shifted to the hands of small

farmers while UJF has shifted their emphasis of operation to factory processing during

the past 15 years. This is a general pattern in all of Lampung where more than 20 large-

scale cassava starch factories are in operation.

UJF has invested heavily, not only in the factories and production fields, but also

to improve the local infrastructure like roads, housing for 8,000 laborers, electricity,

water supply, schools, clinics, mosques, grocery shops, cafeterias, sport and

entertainment facilities, and last but not least, research facilities. UJF now maintains one

of the best managed field experimental plots in Indonesia, which are basically open to

national research organizations. The University of Lampung, the Agricultural University

of Bogor (IPB), the Technical University of Bandung 0TB), and Brawijaya University,

158

among others, have been using the UJF field for their research. While establishing a

commercially viable agro-industrial business is the principal goal of the UJF/GGPC

operation, rural development and better social welfare are equally important long-term

objectives.

Three Way Cooperation

During the 1970s, a modest root crop research program of the Bogor Research

Institute for Food Crops (BORIF) under the Central Research Institute of Food Crops

(CRIFC), was the only institution where research on cassava varietal improvement was

conducted. Based on the national cassava germplasm collection, small-scale hybridization

and selection at Bogor produced a series of improved hybrid clones. While there was

a certain progress in their breeding work, their success was largely limited to the small

scale dual purpose production of West Java. BORIF/CRIFC did not have sufficient

resources to evaluate the advanced breeding materials for large-scale industrial production

multi-locationally or to multiply planting stakes on a large scale.

We established a three-way collaboration in cassava varietal improvement and

dissemination at UJF in 1982, in which UJF provided ample facilities for varietal

selection, multiplication and dissemination to the BORIF/CRIFC cassava program, while

CIAT contributed the basic training of research personnel and additional breeding

materials. Both the breeder of the BORIF program (Roberto Soenarjo) and the UJF

research and development manager (Hardono Nugroho) in the initial years of the

collaborative program, had been participants in a CIAT Cassava Training Course in Cali,

Colombia. From 1983, advanced breeding materials in the form of hybrid seeds have

been introduced to BORIF from CIAT/Colombia and since 1985 from the Thai-CIAT

program. These have been evaluated and selected jointly by the three parties at Umas

Jaya Farm. Multi-location evaluations of the most advanced materials have also been

conducted jointly. It was a new experience for the national program breeder to be able

to evaluate his breeding materials without worrying about the size of experimental plots,

availability of field labor or other expenses. The collaborative program continued even

after the BORIF breeder left for abroad in 1989 and the program is now regarded as the

best functioning cassava varietal development program in Indonesia.

Selection of M-31 (Adira 4)

A clone identified as M-3 1 was one of the breeding materials produced at BORIF

that was taken to UJF for large-scale evaluations. At the second cycle of evaluation, it

became clear that M-31 was outstanding, not only among the 40 clones brought from

Bogor, but also in comparison with the then leading traditional cultivar of the plantation

and the region, Kretek (Table 1). M-31 possessed high yielding capacity, high root dry

matter content, and a good combination of vigorous vegetative growth with comparatively

high harvest index; it also had a good plant type, and uniform and well-shaped roots with

159

white root flesh color, an important trait for starch production.

By 1986, the official release of M-31 was recommended at BORIF and the name

Adira 4 was given. Adira 4 showed its superior capacity for large-scale industrial starch

production, giving a yield up to 80% higher than Kretek (Table 2); moreover, the

adaptability of Adira 4 to drier climates of Central and East Java was also confirmed.

By 1988, large quantities of planting stakes of Adira 4 were available for distribution

outside the UJF plantation.

Varietal Dissemination

We started the distribution of Adira 4 planting stakes in 1987 by donating

packages of long stakes (2500 long stakes each) to 40 cooperatives of small farmers in

Lampung. This activity of giving the stakes of improved cultivars to any interested small

farmer community continues up to the present. A massive distribution followed in 1988

and 1989. A total of approximately 6 million long stakes, enough to plant more than

3,000 ha, have been sold at a nominal price to large-scale plantations in Lampung, South

Sumatra, West Sumatra and Palembang, and to extension units in South Sulawesi, South

Kalimantan, and West-, Central-, and East Java. The area planted with Adira 4 is now

estimated to be more than 100,000 ha in Lampung province alone (Tables 2 and 3;

Figure 1). Adira 4 is still widely known as M-31, the UJF code name, in Lampung

rather than as Adira 4, the BORIF/CRIFC official name. Since Adira 4 has spread to

other provinces of Sumatra, as well as to other outer islands, the total Adira 4 acreage

may now be much more than these figures.

The large-scale adoption of Adira 4 caused substantial economic gains first to the

large plantations and factories; yet, it is now resulting in wide-spread economic benefits

to tens of thousands of small farmers. We shall analyze these effect more in detail in the

subsequent sections.

Analysis of Economic Benefits

1. Production data used

We used the sales value of the products as the basis for measuring economic

effects. Value of sales includes production costs and net profits. The gross production

costs are made up of expenditures for labor, equipment, supplies, maintenance, and

depreciation. At the company management level, net profit rather than the value of sales

may be more critical. However, in the national development context, value of sales may

be a more important indicator of the socio-economic benefits, as it represents

employment, purchasing power and the availability of useful products.

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Year

Figure 1. Area planted with new cassava cultivars (mostly Adira 4) in Lampung,

Sumatra, Indonesia from 1985 to 1996.

164

To concentrate on the most direct monetary effects and avoid possible duplicates

and exaggerations, we used only two measures for the economic gain: additional field

production of fresh cassava roots due to the higher yield of Adira 4, and additional

factory starch production due to the higher starch content of Adira 4. The additional

factory profit generated by the gross additional availability of raw materials is not

accounted for, let alone the additional production of numerous secondary products.

Thus, the real gross additional economic effects are much more than described in this

simple analysis.

The following hard data were available:

1. Area planted with Adira 4 within the UJF campus (Table 2).

2. Yield and starch content data from numerous trials as well as from large commercial

plots (Table 1).

3. UJF survey on cassava planting at 62 municipalities in three regions of Lampung

province during every month from Feb to Sept 1995.

4. Data about cassava acreage in Lampung province from 1985 to 1994 supplied by the

Agriculture Department of Food Crops of Lampung province.

5. On-farm price of fresh cassava roots and starch price for the factory from 1985 to

1996. We used the low price in each 2-5 year period for the analyses.

We used the following information as semi-hard data:

6. UJF estimates of the percentage of total area planted to Adira 4 in three regions of

Lampung.

2. Economic effects within UJF

The first analysis is on the additional monetary gain within the UJF campus in

the past ten years (Table 2). This is strictly based on hard data, and probably the most

reliable economic analysis of this kind, even though the scope is limited to a relatively

small, closed scheme. The new cultivar has been planted in between 0 and 3000 ha

depending on years; it produced an additional 128,000 tons of fresh cassava and 23,000

tons of starch, which led to the additional values of US$ 3.8 million and US$ 4.6

million, respectively, or a total of US$ 8.5 million. This analysis is well in line with the

observations of the last author. The sales value includes a considerable proportion of

production costs; thus, the net profit to the company is smaller than the values presented

above. Nevertheless, it leaves little doubt that the new cultivar has brought in a profit

vastly and positively disproportional to the research investment.

Economic effects in Lampung province

Our field survey estimates the proportion of Adira 4 in the total cassava planted

area to be 75% in North Lampung, where UJF is located, 60% in Central Lampung, and

165

25% in South Lampung. More than 90% of the cassava roots brought by small farmers

to the UJF factory are of Adira 4. In North Lampung, nearly all of the cassava planted

near large starch factories are Adira 4. There are 21 large starch factories in Lampung.

Thus, the projection above may be a reasonable estimate. Extrapolating from data

sources 3, 4 and 6 mentioned above, the total area of Adira 4 is estimated to be presently

about 1 18,000 ha in Lampung (Table 3, Figure 1). The total additional money received

by the producers for the additional fresh root yield due to the adoption of Adira 4 is

estimated to be US$ 85 million (Table 3). The total additional starch value generated

by the higher starch content of Adira 4 is estimated to be US$ 109 million (Table 3).

As of now, monetary benefits generated through the improved starch content of the new

variety are even greater than that generated by the higher fresh root yield of the new

variety (Figure 2). Yet, the total economic effects of US$ 194 million is the figure for

Lampung province alone. The total effects for all over Indonesia must be significantly

larger than this.

4. Estimating direct economic effects to small farmers

Since the great majority of the fresh root producers are now small farmers, we

can happily and safely assume that the US$ 85 million additional profit for the higher

fresh root production went directly to the pockets of small farmers in its near entirety.

How much of the additional profit generated by the higher starch content of the new

cultivar was returned to the farmers depends on what differential price the starch factory

pays to the farmers. If the factory pays the same price for roots of different starch

content (in other words, does not honor or recognize the breeders' and farmers' efforts

to produce higher quality products), all the additional profit would be pocketed by the

factory. At UJF, the factory is paying differential prices to the farmers; thus, a

significant portion of the profit resulting from the higher starch content is being returned

to the small farmers. Yet, there are many , mostly small, factories which do not yet pay

according to starch content. Under any circumstances, larger operators have more access

to larger profit making opportunities. Yet, in cassava as a cash crop for small farmers,

a significant portion of the profit generated by new varieties is surely going directly to

the multitude of small farm families.

Further Progress in Varietal Selection

Varietal selection continues and lines CM4049-2 and CM4031-10 were selected

from the hybrid seed introductions from CIAT/Colombia. Through the CRIFC varietal

naming and release scheme, the Research Institute for Legumes and Tuber Crops

(RILET), located in Malang, East Java, and functioning under CRIFC, named them

Malang 1 and Malang 2, respectively. These are equally high yielding as Adira 4 but

not significantly superior. UJF did not multiply them in a big manner. They are now

still planted in only small areas here and there. Kasetsart 50, a clonal introduction from

166

Thailand, showed excellent results (Table 1) and is currently being multiplied by UJF

for planting in other sites outside UJF and for distribution to interested farmers.

Several new selections are passing through the breeding pipeline (Tables 4 and

5) and they may eventually prove superior to Kasetsart 50. While Kasetsart 50 has

become a universal standard of selection in many parts of Asia, no breeding program

outside Thailand has produced yet anything clearly superior to Kasetsart 50. Our

selection at UJF may be the next program to attain this honor. Aside from the two

highly functional cassava breeding programs in Thailand, one at Rayong Field Crop

Research Center and the other at the site of the Thai Tapioca Development Institute

conducted by Kasetsart University, our program at UJF may be the best functioning

cassava breeding program in Asia.

Pineapple replaced cassava as the most profitable crop at UJF and we may

discontinue large scale cassava plantings within UJF. If we view the on-going cassava

breeding program at UJF as a short-term money making scheme, it might have

accomplished very profitable functions already. On the other hand, since long-term

contribution to the welfare of local communities is one of the important objectives of the

UJF operation, we may continue the program. After all, this is virtually the only cassava

varietal improvement and dissemination program that is producing results in Indonesia

at present. CIAT collaboration here will continue as long as the opportunity for selecting

superior genotypes for small farmers exists.

CONCLUSIONS

Our thirteen years of collaboration offers the following clear messages:

1 . Indisputable success of cassava varietal improvement and dissemination took place

through a private corporation (UJF), which fully utilized the materials and expertise

offered by an international research organization (CIAT), i.e. breeding materials,

training and technical guidance.

2. The contribution of varietal improvement can be quantitatively measured in terms of

additional income generated to small farmers. A hundred million US dollars shared

by hundreds of thousands of poor farmers as additional income has quite different

social effects compared with the same amount of money made by a multi-national

conglomerate.

3. Cassava varietal improvement proves to be one sure vehicle with which to improve

the plight of small farmers.

4. The private sector can efficiently and effectively handle cassava varietal development,

especially the multiplication and dissemination, when government research and

extension institutions need additional research and dissemination capabilities.

167

Table 4. Results of an Advanced Yield Trial at Umas Jaya Farm, Lampung,

Sumatra in 1994/95.

Dry Fresh Root dry Total Harvest

root root matter biomass index

yield yield content yield

Clone Parents (t/ha) (t/ha) (%) (t/ha)

SM 1650-2 CM3306-4 15.9 41.5 38.4 66.6 0.62

Malang 1 CM1015-19xCM849-l 14.4 41.7 34.5 69.5 0.60

Kasetsart 50 Rl x R90 14.3 38.9 36.8 80.6 0.48

Rayong 90 CMC76 x V43 13.9 39.3 35.5 70.1 0.56

CMR30-56-1 CMR23- 17-251 x Rl 13.6 36.5 37.2 57.2 0.63

Mean of all 22 entries 11.2 30.8 36.3 55.0 0.56

Adira 4 (control) = BORIF 528

Kretek (local control)

13.5 36.9 36.6 68.5 0.54

10.1 33.5 30.0 71.5 0.47

Table 5. Results of a Preliminary Yield Trial at Umas Jaya Farm, Lampung, Sumatra in

1994/95.

Clone Parents

Dry Fresh Root dry Total

root root matter biomass

yield yield content yield

(t/ha) (t/ha) (%) (t/ha)

Harvest

index

Thai-CIAT clones

CMR35-42-4 CMR29-60-15 x KU50 18.5 48.0 38.6 90.8 0.53

CMR35-20-1 R5 x CMR28-72-131 18.0 50.0 36.0 76.6 0.65

CMR35-118-7 R60xCMR28-72-131 17.0 46.2 36.8 72.4 0.64

OMR35-30-3 OMR29-20-118 15.1 42.3 35.7 89.5 0.47

CMR35-110-3 Rl x R90 13.7 42.2 32.5 71.1 0.59

Mean of all 14 entries 12.7 34.9 36.5 64.8 0.54

CIAT/Colombia clones

SMI 8 12-6 SG804-5 20.0 52.8 37.8 92.1 0.57

SMI 853-2 CG1141-1 17.2 50.0 34.4 81.8 0.61

SM 1778-2 CG1320-10 16.3 42.7 38.3 77.0 0.55

SMI 879-1 MPar 159 16.3 46.9 34.8 76.2 0.62

SM 1787-1 HMC-1 15.6 46.7 33.5 88.5 0.53

Mean of all 20 entries

Adira 4 (control) = BORIF 528

12.3

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168

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Figure 2. Additional economic effects generated by the adoption of new cassava cultivars

in Lampung province of Sumatra, Indonesiafrom 1985 to 1996.

169

REFERENCES

Hardono Nugroho, J., R. Soenarjo and K. Kawano. 1992. Umas Jaya project - An example of

successful cooperation between the private sector, a national institution and an international

organization. In: R.H. Howeler (Ed.). Cassava Breeding, Agronomy and Utilization Research

in Asia. Proc. 3rd. Regional Workshop, held in Malang, Indonesia. Oct 22-27, 1990.

pp. 162-169.

170

SOCIO-ECONOMIC CONTRIBUTION OF CASSAVA VARIETAL

IMPROVEMENT TO THE SMALL FARMER COMMUNITIES IN ASIA

Kazuo Kawano

ABSTRACT

The success or failure of any large-scale crop breeding program should be measured by

achievement of the following step-by-step goals:

1 ) Establishment of a breeding program

2) Building of effective research capability

3) A large number of genotypes produced and evaluated

4) Selection of superior genotypes

5) A large number of cultivars released

6) A considerable area planted with new cultivars

7) Additional yield and quality as a result of the planting of new cultivars

8) Additional economic benefits generated by the adoption of new cultivars

9) The less privileged strata of society receive the greatest share of the profits

10) Beneficial social changes brought about by the planting of new cultivars

Accomplishing all of these was our wildest dream when we established a major cassava breeding

program at CIAT headquarters in Colombia more than 20 years ago.

The first step towards achieving these goals came in the form of a distinctly higher

yielding capacity of the breeding population within CIAT. When a major part of the CIAT

cassava program extended to the collaborative program in Thailand, a significant improvement

followed in root dry matter content and in adaptation to drier climates. Then, this progress was

transferred to other major national cassava programs in Asia. Many new cultivars were developed

and released, and thanks to the effective involvement of national and private research, extension

and development institutions, the new cultivars are now planted in more than half a million ha in

Asia. The additional economic benefits generated by the additional fresh root yield and higher

starch content of these new cultivars are surpassing 500 million US dollars. More importantly,

at least half of this additional benefit is going directly to the family income of hundreds of

thousands of small farmers. It is fortunate that we have been able to work with the same basic

strategy and the same fundamental objectives throughout the history of nearly a quarter century

of our cassava varietal improvement program. Now, we are beginning to see many of the original

goals being attained.

INTRODUCTION

The spectacular success of new high-yielding varieties of rice (initiated by IRRI)

and wheat (initiated by Rockefeller/CIMMYT wheat program), adapted to high-input

cultural conditions not only increased the production of major food commodities in many

tropical countries, but also convinced administrators of both developed and developing

countries of the benefit of investing in tropical agricultural research. The "Green

Revolution", as it was called, swept the Asian continent in the late-sixties and seventies,

but was limited to relatively well-off farmers in the irrigated areas. The next major

challenge was to raise the productivity and incomes of small farmers in the upland areas.

Cassava, being one of the major crops for small upland farmers in the tropics, but at the

CIAT Asian Cassava Program, Dept. of Agriculture, Chatuchak, Bangkok, Thailand.

171

same time the least researched crop, was yet to be taken as a next target of international

research attention. With this background and a clear expectation of repeating the success

of IRRI's rice varieties with this little-known crop cassava, CIAT established its Cassava

Program in 1972, and the CIAT cassava breeding efforts started in 1973.

Peter R. Jennings, the undisputed mastermind of the Rice Green Revolution of

IRRI earlier in the 1960s, and the pundit of CIAT during the 1970s, challenged every

novice breeder by indicating that any major crop breeding program of an International

Agriculture Research Center should aim at a 100% yield increase, and the success of the

program should be measured only by the area planted with the new varieties and the

economic benefits that were generated by them. Both James H. Cock, then leader of the

CIAT Cassava Program, and myself, who started the CIAT cassava breeding program,

were young and ambitious with a measure of naivety, idealism and audacity. Borrowing

a passage from the Gabriel Garcia Marques' master-piece "Hundred Years of Solitude":

"The world was so new that many things even lacked a name", so free was our program

in defining the basic research structure and so flexible was the administration of CIAT

with a minimum of institutional strait jacketing. Our determination was to double the

physiological productivity of cassava through breeding as a means to contribute to the

improvement of small cassava farmers' income.

In retrospect and with a little bit of hindsight, our overall objective and ambition

were to be measured by the achievement of the following ten intermediate goals, and our

wildest dream was to accomplish all of these:

1) Establishment of a breeding program

2) Building of effective research capability

3) A large number of genotypes produced and evaluated

4) Selection of superior genotypes

5) A large number of cultivars released

6) A considerable area planted with new cultivars

7) Additional yield and quality as a result of the planting of new cultivars

8) Additional economic benefits generated by the adoption of new cultivars

9) The less privileged strata of society receive the greatest share of the profits

10) Beneficial social changes brought about by the planting of new cultivars

We were full of enthusiasm and optimism. We felt that we, the field workers,

were the principal players of the whole game. Quixotic as it might have looked, this was

the spirit of the young CIAT with which I started the cassava breeding program.

Organizing the CIAT Cassava Breeding Program and Enhancing National Programs

I have been writing on the history of CIAT headquarter breeding program and

our collaborative breeding program with the Department of Agriculture, Thailand on

many occasions, including in the CIAT Annual Reports and in the past Proceedings of

this Asian Cassava Research Workshop. From these, at least the following points

172

deserve special mention. We started the breeding program with a vast genetic diversity,

i.e. a collection of 2,200 local cultivars from the center of origin and diversification,

instead of basing the program on a small number of preselected elite germplasm. After

many cycles of intensive hybridizations and selections, our breeding populations show

no sign yet of reaching a plateau of yield selection. This may be a result of the inclusion

of a large genetic variability from the beginning. As the big "bang" of organic evolution

in the Cambrian period suggests, the condition in the beginning may hold a lasting

influence up to the very late stages of development. Then, modeling after the

development of the CIAT breeding program, many national cassava breeding programs

were established and have been upgraded.

Generation and Distribution of Breeding Materials

Some 450 thousand hybrid seeds from CIAT/Colombia have been distributed to

the national breeding programs in Asia (Table 1). Thanks to the cooperation of the

Rayong Field Crops Research Center of the Department of Agriculture (DOA) of

Thailand, another 100 thousand hybrid seeds have been distributed from the Thai-CIAT

program to other Asian national programs as well as to CIAT/Colombia through the

CIAT Asian Cassava Program (Table 2). These breeding materials have been offering

immediate opportunities for varietal selection, as well as the means to organize and

improve the breeding operations of the national programs.

Upgrading Yield Capacity and Adaptation of Breeding Populations

We continue our joint efforts by the collaborative program in Rayong, by CIAT

headquarters in Colombia and by the cassava breeders of national programs. In the Thai-

CIAT program, we have been using the mean yield data of all clonal entries in the

Regional Trial network relative to control as a way to measure breeding progress,

because this represent the value of immediately available materials, as well as the

potential of on-going hybrid populations. These advanced clonal entries form the basis

of the hybridization program at Rayong Center. Since the hybrid seeds from the Rayong

program are now a vital source of selection in many national programs in Asia, the

advance in clonal selection in Thailand also effects the potential of yield selection in other

national cassava programs in the near future.

During the past years satisfactory progress was made in selecting for high fresh

root yield (Figure 1), root dry matter content (Figure 2), and total biomass productivity

(Figure 3). The harvest index has been stable at a relatively high level during the past

ten years (Figure 4). Coming from the level of 1982 when data-taking started, we have

made considerable progress. Adding to this the very substantial improvements made

during the earliest years of CIAT headquarters breeding, which constituted the basis for

the subsequent progress in Asia, the mean yield capacity of the present breeding

population, i.e. the average yielding capacity of the hybrid seed population distributed

173

to national programs, is 100% higher than of the population during the early 1970s.

Progress in each national program is reported by each program elsewhere in this

Workshop Proceedings.

Varietal Dissemination

The number of CIAT-related cultivars officially released in Asian national

programs has now passed 25. The number of clones pre-released and waiting for official

release or left to the plantings by farmers, a very typical manner of varietal dissemination

in many parts of the world even now, far exceeds this number.

In Thailand where statistics are available on the area planted with each cultivar

from data collected by the Department of Agricultural Extension, the total area planted

with five new cultivars is given as 376,250 ha in the 1995/96 planting season (Figure 5).

In Indonesia, hard data and an extrapolation from these indicate that new cultivars are

now planted in more than 1 10,000 ha (Palupi etal., this Proceeding). In Vietnam, where

the CIAT collaboration started much later than in other national programs, progress has

been highly satisfactory, and good observation data show that the area planted with the

new cultivars was more than 6,500 ha in the 1995/96 season, and is now estimated to be

15,000 ha in the middle of the 1996 planting season (Figure 6 and also see other reports

in this Proceeding). In the Philippines where no detailed data are available, the area with

new cultivars is estimated to be at least 3,000 ha (see Mariscal and Bergantin, in this

Proceedings). Thus, the total area planted to CIAT-related cassava cultivars in Asia

appears to have just passed the half a million ha line this year.

Economic Effects

I used the sales value of the products as the basis for measuring economic effects.

Value of sales includes production costs and net profits. The gross production costs are

made up of expenditures for labor, equipment, supplies, maintenance and depreciation.

For regular commercial operations, net profit rather than the value of sales may be more

critical. However, in the national development context, value of sales may be a more

important indicator of the socio-economic benefits, as it represents employment,

purchasing power and the availability of useful products.

To concentrate mainly on direct monetary effects and avoid possible duplicates,

I used only two measures for the economic gain; additional (or reduced) field production

of fresh cassava roots due to the higher (or lower) yield of new cultivars, and the

additional factory starch (or chips) production due to the higher starch (or dry matter)

content of new cultivars compared with the traditional cultivars. The additional factory

profit generated by the gross additional availability of raw materials is not accounted for,

let alone the additional production of numerous secondary products. Thus, the real gross

additional economic benefits are much greater than described in these simple analyses.

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CIAT collaborative cassava breeding program in Rayong, Thailand.

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179

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For the yield and starch content advantage (or disadvantage) resulting from the

adoption of new cultivars, I used the means of many regional trials and on-farm trials

(Tables 3 and 4). The absolute yield figures represent what advanced farmers would be

able to obtain in their fields and the yield difference from the traditional cultivar, which

actually matter more, would represent what could be obtained under a wide range of

farming conditions. For on-farm price of fresh cassava roots and factory starch price,

I used the low price in each 2-5 year period from 1985 to 1996.

One nagging question that always arises when discussing cassava production is

the issue of marketing. Such questions as "Can the farmers always find the market?" or

"Can you assume that all the producers sold their fresh cassava at the market price?" are

valid and these are real concerns, especially for small farmers who grow cassava for

fresh human consumption. We have been dealing mainly with the increasing

commercialization of cassava, i.e. the processing of starch or chips, and we have been

developing new cultivars mainly suited for factory processing. Most farmers who adopt

new cultivars are growing cassava as a cash crop for factory processing. The cassava

market for starch processing is now rapidly expanding in Asia. It must be reasonably

safe to assume that all the additional productions herein reported have led to additional

cash income almost in their entirety, and the unabating adoption of new high-yielding

cultivars is indirect proof for this. The subsequent analyses show that cassava is clearly

an attractive means for small farmers to improve their cash income.

In Thailand the varietal adoption started with Rayong 3, which has a higher

starch content that the traditional variety Rayong 1 but may produce lower fresh root

yields. Farmers who adopted Rayong 3 have been actually losing money by the sales of

fresh roots but gained money from its higher start content. Only recently, when new

cultivars that have both high fresh root yield and high starch content started to replace

Rayong 3, did benefits result from both higher starch and higher root yields (Figure 7).

The additional economic effects caused by the higher starch content has been highly

significant. Until recently, virtually all the economic benefits in Thailand have been due

to the higher starch content of new cultivars.

In Indonesia, the advantage of new cultivars is clearly in both fresh yield and

starch content; thus, the additional fresh root yields in the fields and the additional starch

production in the factories both produced substantial economic gains (Palupi et al., in this

Proceedings).

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185

In Vietnam, more money has been made from the sale of planting stakes of new

cultivars than from fresh root harvests and higher starch content, although the benefits

caused by the additional fresh root production and the additional starch production will

probably outstrip the stake sale as of the 1996/97 season (Figure 8).

Throughout all this process, the advantage of higher starch content was highly

significant. It is the higher starch content rather than the higher fresh yield of new

cultivars that accelerated the adoption of new cultivars. The total economic benefits due

to the superior yield and quality of the new cultivars, accumulated up to now, is

estimated to be 479 million US dollars.

In this article I am analyzing primarily the economic effects caused by the

additional root yield and additional starch content of the CIAT-related new cultivars.

Yet, when we consider the history of the whole cassava processing industry in Asia, the

establishment and development of large export markets for cassava products by Thai

entrepreneurs, and the selection of cultivar Rayong 1, which has been the backbone of

the Thai cassava industry, are by far the most significant factors. The monetary

contributions of these must be in the billions of US dollars. The greatness of Rayong 1

is not limited to the immensely successful field production in the past two or three

decades, but also extends to its role as an effective cross parents, as it produced Rayong

60 and Kasetsart 50, among others, through hybridization with the introduced parents

from CIAT/Colombia. The contribution of Thai farmers who selected Rayong 1 should

always be remembered.

Profit to Small Farmers

Virtually all the cassava production takes place in small farmers' fields and all the

roots in Thailand are sold to cassava processors. In Vietnam also, all the cassava is

produced by small farmers, and at present, those advanced cassava farmers who have

adopted the new cultivars sell virtually all the harvested roots to the processors. In

Indonesia and the Philippines, some cassava is produced in large plantations; yet, the

majority of production takes place in small farmers' fields. Thus, we can assume that

virtually all the additional economic benefits generated by the higher fresh root yield of

new cultivars are entering directly into the pockets of small farmers.

On the other hand, how much of the additional profit generated by the higher

starch content of new cultivars is shared by the farmers depends on what differential price

starch factories (or chipping plants) pay to the farmers. If the factory pays the same

price for roots of different starch content (in other words, does not honor or recognize

the breeders' and farmers' efforts to produce higher quality products), all the additional

profit will be absorbed by the factory.

Analysis of a price scheme used at a starch factory in Rayong, Thailand indicates

that more than half of the cost of starch production is the cost of fresh cassava, even

using cassava roots of high starch content (Table 5), suggesting that in general a fair

186

price is paid to the producers. More interesting is the question on what proportion of the

additional starch produced due to the higher starch content of the new varieties is

returned to the farmers (Table 5). Since the factory can benefit from the increased

amount of final product, its business can still be viable even if the factory fully (100%)

compensates the farmers for the higher starch content. In effect, most factories return

between 55 and 100 % of the value of additional starch production caused by higher

starch content of the raw material to the farmers.

All in all, the scheme is not entirely unfair to the farmers. The initial adoption

of Rayong 3 testifies this (Figure 5). While the farmers were losing money by the

reduced sales of fresh roots, due to the lower fresh root yield of Rayong 3 compared with

that of the traditional cultivar Rayong 1, they must have been receiving reasonable

compensation from the factories for the higher starch content of their products. If the

factories had not given a fair compensation, the planting of Rayong 3 would have halted

immediately. We can safely assume that a substantial portion, more than a half, of the

480 million US dollars so far generated by the adoption of new cassava cultivars has

entered the household income of small farmers.

Social Effects

In addition to the very basic expectation of strengthening the cassava status as an

efficient crop for increasing the cash income of small farmers, our work is expected to

contribute to the improvement of the efficiency of factory processing as well. Higher

production and processing efficiency could lead to a higher competitiveness of the

products domestically and on international markets. All of these are taking place already

although the magnitude of the effect differs among countries.

Cassava is often cited as a crop conducive to soil degradation. Much efforts are

directed to identify and enhance adoption of soil management practices that lessen soil

erosion or mineral nutrient exhaustion. While individual methods are important and

indispensable components of soil management, a more fundamental requirement is to first

upgrade the economic situation of farmers, so that farmers can consider the long term

future of their farming operation and start adopting better soil management practices. As

cassava processing becomes more lucrative, there will be stronger concerns for making

the whole cassava production and processing industry more sustainable. It is yet to be

seen whether the additional production efficiency generated by the new cassava cultivars

would eventually add up to cutting the vicious cycle of poverty and environmental

degradation.

Epilogue

It is fortunate that I have been able to work with the same basic strategy and the

same fundamental objectives throughout the nearly a quarter century history of the CIAT

Cassava Program. Generating useful breeding materials, offering them to national

187

programs and participating in their selection have been the basic style of the CIAT

cassava breeding program. Many of the national breeding programs represented in this

Workshop have been highly responsive to utilizing our materials and expertise. They are

now highly successful in selecting truly useful cultivars and contributing to the farmers.

We are proud that, among so many so-called research networks, our Asian cassava

breeding network is one that is producing truly meaningful results. Now that we are

beginning to see the results of our collaborative work, it is all the more fortunate that we

can measure the achievement of our long time goals by the same original criteria defined

when I was full of boyish naivety and idealism 25 years ago.

Acknowledgement

None of the good results quoted in this report is the work of CIAT alone. They

all are the result of our collaborative work with national programs. My personal

involvement in producing research results ranges from nearly total, such as the

development of Rayong 60 and Rayong 5 in Thailand and KM-60 in Vietnam, to

marginal, such as the release of SC8002 in China. The breeding materials and technical

data thus produced in our collaboration with national programs primarily belong to the

national programs. I appreciate the good collaboration of national cassava breeding

programs in Asia. Among these, the contribution of the Rayong Field Crops Research

Center, Department of Agriculture, Thailand, has been particularly significant in jointly

producing advanced breeding materials to be contributed to other Asian programs, as well

as to enrich the germplasm and breeding populations back at CIAT Headquarters,

Colombia. We are all greatly indebted to the collaboration from the Thai cassava

research community.

188

Table 5. Fresh cassava and starch price scheme and distribution of additional profit

caused by higher starch content of cassava roots between farmers and

starch factories in Thailand.

Raw material cost

as proportion of Share (%) of additional profit caused

Root starch Fresh cassava value of starch by 1 % higher root starch content

content" price produced3)

(%) (Baht/t)2) (%) Fresh root seller Starch factory

30 920 51 65 35

29 900 52 65 35

28 880 52 64 36

27 860 53 63 37

26 840 54 62 38

25 820 55 61 39

24 800 56 61 39

23 780 57 59 41

22 760 58 58 42

21 740 59 57 43

20 720 60 56 44

19 690 61 83 17

18 660 61 82 18

17 630 62 81 19

16 600 63 80 20

15 570 63 79 21

"Determined by Reihamnn scale.

2)Price data for different starch content at Rayong in Aug 1996; US$ 1 .00 = Bant 25.00.

3)Based on starch price of US$ 240/t.

189

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Figure 7. Additional economic effects generated by the adoption of new cassava in

Thailand between 1985/86 and 1995/96.

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191

CASSAVA AGRONOMY RESEARCH IN CHINA

Zhang Weite1, Lin Xiong\ Li Kaimian1, Huang Jie\ Tian Yinong2, Lee Jun2

and Fu QuohuP

ABSTRACT

Through cooperation with CIAT, national programs in China have paid more and more

attention to cassava agronomy research and a lot of progress has been made. This paper describes

briefly the most common cropping systems and production practices presently used by farmers.

It also reviews the results of research on soil/crop management, with emphasis on soil fertility

maintenance and soil erosion control, during the past decade.

In China, cassava is usually planted from Jan-May, while it is harvested from Nov-Mar.

The plant population is about 10,000-12,000 plants/ha under normal conditions, while the

population could increase to 15,000-18,000 plants/ha in poor soils.

Results of soil erosion control trials showed that two treatments, i.e. no-tillage but

making a planting hole (30x30 cm) by hoe, or complete land preparation followed by contour

ridging, not only increased cassava yields, but also decreased soil erosion. However, soil loss was

very serious with complete land preparation but without ridging. Long-term fertilization trials

conducted in CATAS, GSCRI and UCRI, indicate that cassava yields increased significantly with

the application of N and K. Increasing the N application from 50 to 200 kg/ha while maintaining

a constant rate of 100 kg K2O and 50 kg P2Os/ha, cassava yields increased significantly, but the

root starch content decreased. In contrast, both cassava yield and root starch content increased

with an increase in K application from 50 kg to 200 kg K2O/ha, while maintaining a constant rate

of 100 kg N and 50 kg P2Os/ha. Cassava intercropped with watermelon produced the highest

economic returns, but soil erosion was controlled most efficiently by intercropping with peanut.

INTRODUCTION

The Status of Cassava Production and Development in China

In China, cassava could be cultivated in the areas south of the Qinling mountain

and Huaihe river, with mean annual temperatures above 18°C and a frost-free period of

more than eight months of the year. Therefore, there is a tremendous potential for

further expansion of the cassava production area. The total cassava area in China has

now reached 450,000 ha. Recently, cassava processing and utilization have developed

more in-depth, and the production of cassava-based products has increased from 30 to

70% . Cassava is turning into a very important upland crop in the southern part of China.

The production of cassava has changed from a scattered and backward crop into

one that is farmed intensively. According to statistics in Hainan, there are now ten

enterprises cultivating 100-300 ha of cassava, and the number of farmers who plant 3-10

1 Chinese Academy ofTropical and Agricultural Sciences (CATAS), Danzhou, Hainan, China.

2 Guangxi Subtropical Crops Research Institute (GSCRI), Nanning, Guangxi, China.

3 Upland Crops Research Institute (UCRI) of the Guangdong Acad. Agric. Sciences,

Guangzhou, Guangdong, China.

192

ha has been increasing year after year. Thus, cassava production is moving towards

more mechanization and more intensive farming, with greater use of chemical fertilizers

and other farm chemicals. According to the statistics of Hainan, about 30% of the total

farm work is mechanized, which is achieved by working in commodity production units;

this has reached 70% in a few units. Over 60% of these units use herbicides and

chemical fertilizers.

Yunnan province is a new area for cassava production. According to the

statistics, in 1990 the total cassava cultivated area was 7,000 ha. However, the area

under cassava has recently increased as more and more planting material was introduced

from Guangxi. Presently, in Honghe district of Yunnan alone, the area under cassava

has reached 16,000 ha. It is estimated that the cassava area in Yunnan will be 20,000-

30,000 ha.

Improved Varieties

Research on cassava breeding and cultivation in China began in 1914. Most of

the cassava varieties have been introduced from abroad, like those presently known as

SC201 and SC205; these were both introduced to China in the 1940s and 50s. At that

time the number of cultivars was very limited. Since 1958 China has been collecting and

evaluating cassava germplasm, and has been doing research on cassava breeding and

agronomy. The edible cultivar SC6068 has been released and popularized in the early

1980s. In recent years, with the accelerated development of cassava production and

processing, new varieties with high yield potential and starch content are urgently needed.

In Guangdong, Guangxi and Hainan provinces, local institutes started research on cassava

breeding. With the cooperation and support of CIAT, and after many years of hard

work, CATAS released SC124, SC8013 and SC8002, and has selected some advanced

clones, such as OMR33-10-4; Guangdong has selected Nanzhi 188, SC8002, and more

recently 901531; while Guangxi selected SMI 113-1.

CASSAVA AGRONOMY RESEARCH IN CHINA

Cultural Practices for Erosion Control

During spring and summer soil erosion is serious in southern China, due to the

monsoon climate, characterized by high temperatures and heavy and concentrated rainfall .

Farmers usually build terraced fields or practice contour ridging to prevent soil erosion.

This method has been mostly adopted in Guangdong and Guangxi provinces. But in the

plains or in areas with gentle slopes, which usually have a high population density and

thus less available land, farmers generally plant cassava intercropped with early-maturing

and short-statured crops. This is not only very effective in reducing soil loss, but also

increases the multiple crop index and has economic benefits.

From 1990 to 1992, researchers at GSCRI in Nanning, Guangxi, conducted an

193

erosion control trial on the effect of different cultural practices on cassava yields and soil

loss due to erosion. It can be seen from Table 1 that contour ridging with fertilizer

application was most effective in reducing erosion, followed by intercropping with peanut

and planting at closer spacing. Method of planting (vertical or horizontal) had no

significant effect on erosion. Researchers at CATAS in Hainan also conducted erosion

control trials and obtained similar results. It can be seen in Table 2 that twice plowing,

followed by twice discing and contour ridging increased the yield by 5% and reduced soil

loss by 38% compared to the same tillage method but without ridging. Preparation of

either big or small planting holes decreased yields by 0.8 and 8.7% and reduced soil loss

by 40 and 36%, respectively, compared with twice plowing and discing but without

ridging. Plowing and discing increased yields compared with minimum or zero tillage

but also caused more soil erosion. As farmers in Hainan tend to have more land but less

labor, they usually plant cassava with zero tillage. This practice results in somewhat

lower yields, but is quite effective in reducing erosion. In Guangdong and Guangxi,

there are more people but there is less available land. On flat or gently sloping land

farmers normally use tractors or cattle to plow and disc, and then plant cassava

intercropped with other crops; this can increase yields and economic benefits, reduce

costs and erosion, while maintaining soil fertility.

Table 3 shows the results of erosion control trials conducted at CATAS.

Fertilizer application with either contour ridging or peanut intercropping increased

cassava yields by 37 and 26% and reduced soil losses by 42 and 29%, respectively,

compared with the same non-fertilized treatments. Similar data from a soil erosion

control trial conducted for three years at CSCRI in Nanning (Table 4) indicate that

contour ridging, peanut intercropping and vetiver grass contour hedgerows were very

effective in reducing erosion, while also increasing cassava yields.

In recent years, in the gently sloping and highly populated regions of Guangdong

and Guangxi, farmers plant cassava intercropped with early-maturing and short-statured

crops, such as watermelon, peanut, soybean etc. This not only increases yields and gross

income, but also reduces soil losses due to erosion. However, with the development of

a market economy, in order to increase profits farmers tend to plant cassava with

intensive land preparation and without any cultural practices to control erosion. Soil

erosion may become the major restriction for cassava production in the future.

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Cropping Systems

Cassava is an annual crop in China. The cropping systems can be classified as

either monoculture, intercropping, interplanting, continuous cropping or rotational

cropping. Monoculture is the major cropping system, and is the common practice in the

mountainous or semi-mountainous areas, where there are less people but there is more

land. The common method of land preparation is either reduced tillage or zero tillage.

Land preparation consisting of plowing and discing increases root yields but also

increases the costs and may cause serious erosion. Therefore, in sloping areas, planting

cassava in a monoculture system with intensive tillage should be done only with contour

ridging, in order to reduce soil losses by erosion.

Intercropping and interplanting is usually carried out in the plains and on gentle

slopes, where the population density tends to be high. Land preparation is intensive and

results in a good income. According to an investigation done by GSCRI, when cassava

was intercropped with watermelon, the income was increased by 30,000-75,000 yuan/ha,

cassava intercropped with watermelon for seed increased income by 7,500-10,500

yuan/ha, while cassava intercropped with peanut increased income 4,500-7,500 yuan/ha.

Table 5 shows that when cassava was intercropped with peanut or watermelon for seed,

both cassava yields and income were increased, while this system will also reduce soil

loss. This cropping system should be popularized.

A cassava rotation cropping system is usually adopted in the mountainous

regions, where the slopes are steep and soil loss is serious. Farmers rarely apply

fertilizers, so, after planting cassava for 2-3 years, the soil nutrients are exhausted and

yield have come down. In Yunnan and Hainan, farmers usually leave the land in fallow

until the soil fertility has recovered. In the flat areas or gentle hills, farmers usually

rotate with sugarcane or other crops. In sugarcane production areas, cassava is rotated

with sugarcane after the latter has been planted for three years. This rotation can give

good yields of both sugarcane and cassava.

Time of Planting and Harvesting

The climatical conditions in southern China are characterized by high

temperatures and abundance of rainfall in the spring and summer, but rather cold and

dry, sometimes with frost, in the autumn and winter. It is difficult for cassava to live

through the winter. After many years of experience with cassava, farmers have

determined the time of planting and harvesting that is most suitable for the climatical

conditions in China. Cassava is usually planted in the spring, and when the temperature

is high and there is abundance of rainfall in the summer, cassava grows rapidly. During

the autumn the temperature and rainfall drop; this is a good time for cassava root

production and the accumulation of starch. This is followed by the root harvest in

winter.

From 1990 to 1994, an expertiment was conducted at CATAS in Hainan to

199

determine the optimum time for planting and harvesting cassava. In this trial, cassava

was planted monthly and was harvested at either 8 or 12 months, using two varieties and

four replications. The result (Figure 1) indicated that when cassava was harvested at 8

months, the highest yield was obtained when cassava was planted in Feb-May. When

cassava was harvested at 12 months, the highest yield was obtained when cassava was

planted in May-June, but in two out of three years cassava yields were not greatly

affected by date of planting. The highest starch content was obtained by harvesting in

Dec-March, inrespective of whether cassava was harvested at 8 or 12 months. The root

yield at 8 months after planting was positively correlated both with the average

temperature and rainfall during the 3d, 4th and 5th months after planting and this

relationship was highly significant (Figure 2). The starch content was significantly and

negatively correlated with the mean temperature during the last month before harvest:

r = -0.770~~ and r = -0.732" for harvests of SC205 at 8 and 12 months, respectively

(Zhang Weite, 1996). Root starch content was also negatively correlated with rainfall

during the month prior to harvest, but the correlation was barely significant (r = 0.48~ for

SC205 harvested at 8 months). These research results correspond well with the actual

farmers practice. It made it clear that the time of planting and harvesting in China as

practiced by farmers is very suitable for the existing climatical conditions. However, the

research results indicate that in Hainan province cassava can be planted almost any time

of the year as long as roots are harvested after a full 12-month cycle.

Table 5. Yield and gross income of two intercropping systems as compared to

monoculture cassava in Qujiang county, Guangdong, China.

Cassava Cassava Intercrop Intercrop Total gross

root yield income yield income income

(t/ha) (Y/ha) (t/ha) (Y/ha) (Y/ha)

Cassava 13.50 4500 - - 4.500

Cassava+ Peanut 15.12 5040 2.5 5.000 10.040

Cassava+ watermelon seeds 18.00 6000 0.6 8.400 14.400

"Prices: cassava fresh roots: Y 0.33/kg

peanut dry pods: 2.00/kg

watermelon seeds: 14.00/kg

Source: Qujiang Agric. Bureau of Guangdong, 1988 (personal communication)

200

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Figure 1. Cassava root starch content (top) and root yield (bottom) averaged over three

varieties and three cropping cycles, when planted during different months

of the year at CATAS, Danzhou, Hainan, China, and harvested after either

8 or 12 months.-

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Average rainfall (mm) during the 3d. 4th and 5th month after planting

Figure 2. Relation between root yield of cassava cultivar SC205, harvested at 8 months,

and the average mean temperature (top) or rainfall (bottom) during the 3d

4th and 5th month after planting in SCATC, Hainan, China. Data are for

36 monthly plantingsfrom 1990 to 1993.

202

Planting Methods

In China, the method of cassava planting is different in different areas.

Horizontal planting is normally practiced in steep land with zero tillage, while inclined

planting is mostly used in the soft soil after tillage; vertical planting is sometimes adopted

in regions with strong winds. Horizontal planting is easy to do and requires less labor,

but sprouting is slow and percent germination may be low, resulting in lower yields.

Vertical and inclined planting requires more labor, but the sprouting of stakes is fast and

the percent germination is high; the root yield is also quiet good.

Table 6 shows the results of two planting method trials conducted at GSCRI

from 1990 to 1992, and in CATAS in 1994. In both sites inclined planting produced

highest yields, while horizontal planting produced the lowest. Vertical and inclined

planting resulted in a higher percent germination at one month after planting than did

horizontal planting. Ridging resulted in a lower percent germination than planting on the

flat.

Table 6. Effect of stake planting position and ridging on cassava yield and

germination at 1 month in GSCRI, Nanning, Guangxi, and in CATAS,

Danzhou, Hainan, China. Data are the average for SC201 and SC205 in

CSCRI, and for SC205 and SC124 at CATAS.

Planting Position

GSCRI (1990-1992) CATAS (1994)

Germination"

(%)

Root yield2)

(t/ha)

Root yield

(t/ha)

Horizontal

-ridging 61.5 11.7 20.0

-no ridging 67.4 10.9 18.6

Inclined

-ridging 66.4 13.0 25.3

-no ridging 78.1 11.5 16.9

Vertical

-ridging 82.8 11.1 19.4

-no ridging 85.8 11.2 18.5

l) Average of 1991 and 1992 (no data taken in 1990)

5 Average of 1990 and 1992 (no harvest in 1991 due to drought)

203

Field Management of Cassava

As cassava is more and more produced under intensive farming practices, the old

way of field management is no longer suitable. Cassava field management will move

towards mechanized farming and more use of chemicals. In China weeds are usually

controlled 2-3 times per year. Hand weeding costs too much labor, the work efficiency

is low, one person weeding in one day on average 250-330 m2 (30-40 mandays/ha). Due

to the development of a market economy, the cassava planting area per farmer has been

increasing year after year, now often being around 3-5 ha; in some areas more than 10

ha. Thus, hand weeding is no longer suitable for this type of cassava production. The

use of pre-emergence herbicides is now in common use in Hainan; mechanized farming

has also been introduced and has been practiced by some enterprises and companies, such

as the Siyueten farm in Changjiang county of Hainan. Plowing, harrowing, stake cutting,

contour ridging, planting, fertilizing, weeding, harvesting and root chipping are almost

all done by machinery. In 1995 twenty ha and in 1996 one hundred ha of cassava were

planted by machinery in this farm. The cost of production was reduced 30-40% and

work efficiency has been raised 7-8 times. This is the way forward for intensive cassava

farming in China.

Fertilization

The long-term fertility trials conducted in Guangdong, Guangxi and Hainan

showed that when cassava was grown continuously in the same field, the combination of

100 kg N, 25 kg P205 and 100 kg K20/ha generally produced the highest yields and

profits. In all three locations cassava responded mainly to the application of N, followed

by K, while the response to P was generally not statistically significant, except at UCRI

in Guangzhou (Figure 3). Application of 5-10 t/ha of pig manure in addition to modest

rates of N, P and K further increased cassava yields in Nanning, but applications of

"burned soil", i.e. a mixture of leaves and twigs slowly burned together with soil, had

no significant effects on yield even at high application rates of 30-60 t/ha. Applications

of K tended to increase the starch content of roots, applications of N tended to decrease

starch while that of P had no significant effect (Figure 4).

In a rate of fertilizer application trial, conducted in CATAS, cassava yields

increased with increasing amounts of fertilizer applied; the application of 400-900 kg/ha

of 15-15-15 compound fertilizer gave the highest profits, as shown in Table 7.

Table 8 shows the effect of N, P and K, applied singly or combined, on cassava

yields in a trial conducted at CATAS from 1989 to 1990. Combined application of N,

P and K was better than that of any single nutrient, and the application of N alone or NK

were better than that of P or K alone or in combination.

Table 9 shows the results of a time-of-fertilizer-application trial conducted at

CATAS in 1988. A single application at 30 days after planting or a split application at

204

30 and 90 days resulted in higher yields than later applications. When fertilizer

application was postponed, the yield and the number of roots decreased. There was no

significant difference between a single application and a split application using the same

total amount of fertilizer.

Table 7. Effect of different amounts of applied 15-15-15 compound fertilizer on

cassava root yield and net income when cassava, SC205,was planted at

CATAS, Danzhou, Hainan, China in 1988 and 1989.

Amount of Cassava root Gross Fertilizer Net

fertilizer yield(t/ha) income

(Y/ha)"

costs

(Y/ha)

income

(kg/ha)

1988 1989 Average

(Y/ha)2)

0 18.6 21.8 20.2 2828 0 2828

150 23.0 31.6 27.3 3822 75 3747

300 27.2 27.3 27.2 3808 150 3658

400 28.2 38.9 33.5 4690 200 4490

900 35.6 34.1 34.8 4872 450 4422

LSD (0.05) 7.2 4.2

(0.01) 10.1 5.9

1) Prices: Cassava fresh roots: Y140/ton

15-15-15 fertilizers: 0.5/kg

2) Net income= gross income minus fertilizer costs.

205

Table 8. Effect of N, P and K application, either single or in combination, on the

fresh root yield (t/ha) of cassava, SC205, planted in CATAS, Danzhou,

Hainan, China from 1988 to 1990.

Treatments 1988 1989 1990 Average

No NPK 15.0 23.1 17.5 18.5

N 16.3 29.5 28.0 24.6

P 20.0 25.3 21.7 22.3

K 19.3 28.6 19.7 22.5

NP 16.8 27.7 22.8 22.4

NK 21.8 31.1 33.7 28.9

PK 22.7 28.5 22.7 24.6

NPK 24.8 34.7 30.2 29.9

Table 9. Effect of time of application of fertilizers on cassava root numbers and root

yield at CATAS, Danzhou, Hainan, China, in 1988.

Root Root yield

numbers/plant (t/ha)

Check without fertilizers 8.5 14.5

Fertilizers applied at:

30 days after planting




Fertilizers applied at:

30 and 90 days

60 and 120 days

LSD (0.05)

(0.01)

11.8 27.2

9.0 24.8

8.5 24.2

7.9 22.0

11.1 27.5

9.7 23.7

2.3 4.9

3.1 7.5

206

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Figure 3. Effect ofannual applications of various levels ofN, P and K on the root yields

of two cassava cultivars grown for the 4th consecutive year at UCRI in

Guangzhou, Guangdong,for the 7th year at GSCRI in Nanning, Guangxi, and

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208

Harvesting Methods

Cassava harvesting methods in China can be divided into hand harvesting and

mechanical harvesting. Harvesting by hand is the most common. Hand harvesting

requires heavy work and has low efficiency, usually requiring 30 mandays/ha.

Mechanical harvesting is rather light work and has high efficiency; on average one

machine can harvest 0.4-0.5 ha per day. In the 1970s and 80s, Xijiang State Farm in

Guangxi was a special cassava farm; over 70% of cassava farming work was done by

machinery. But later the farm changed to cultivate other crops, and the machinery was

left unused. In 1995, Siyueten Farm in Changjiang county, Hainan, began to develop

cassava machinery. Now 80% of cassava work on that farm is done by machinery.

Production costs have been reduced by one-third, and productivity has increased

markedly.

Stem Storage

Due to the cold and dry weather in winter, sometimes with frost, the cassava

harvesting time in China is normally from Nov to March, and planting time from Jan to

April. Harvesting must be done before the onset of frost to guarantee that good quality

stakes can be stored for use next year. In the north, the cold weather arrives earlier and

lasts longer. During the winter cassava may suffer seriously from frost. Thus, in the

north the cassava harvest time is from Nov to Jan and planting time from March to April.

Thus, the period of stake storage is 4-5 months. In the south, the cold weather arrives

later and lasts only a short time, so cassava rarely suffers from frost. Therefore, the

harvest is usually done from Dec to March and planting from Jan to April. Thus, the

storage method of stakes is different in the south and the north. In the south stems are

usually stacked under the shade of trees, and then the stems are covered with dry straw.

If the weather is very dry, water is splashed on the stems. Stem storage is light work

and easy to do. But in the north, the stems are normally stored in soil trenches or pits.

Trenches or pits are dug in a southern exposure and in more elevated areas. The stems

are bundled and placed in the trenches or pits, and are then covered with straw and soil,

allowing some air ventilation. It is important to assure that the trenches do not get

waterlogged. Stem storage in the northern regions is heavy work, and if something is

done wrong, it can cause stake damage. This is a principal sector constraint for cassava

production in the northern part of China.

General Recommendations

Table 10 summarizes some general recommendations for cassava production in

China based on results obtained from research conducted at various institutes during the

past ten years.

209

Table 10. Recommended cultural practices for sustainable cassava production in

China.

1. Variety: use high yielding and vigorous varieties:

SC 201: tolerant to poor soils and cold climate

SC 205: high yield in better soils

SC 124: high yield and cold tolerant

SC 8002: high yield and cold tolerant

SC 8013: high yield and typhoon tolerant

2. Planting time: Guangdong/Guangxi: March-April

Hainan: Feb-May or year-round if harvested at 12

months

3. Land preparation: plow once or twice at 15-20 cm depth with tractor or oxen;

on gentle slopes: make contour ridges after plowing

on steep slopes: plow with oxen or prepare planting holes

with hoe

4. Planting material: select healthy 10-1 1 month old plants; store stems in frost-

free location;

cut 15-25 cm long stakes after eliminating dry portion of

stem

5. Planting method: inclined or vertical with buds facing up, 5-10 cm deep;

plant on ridges if soil is wet, on flat if very dry

5-10 t/ha of manure incorporated before planting

50 kg N/ha as urea

20 kg P205/ha as simple or triple superphosphate (or

thermo-phosphate if soil is low in Mg)

50-80 kg K20/ha as KC1

6. Fertilization:

N, P and K applied at first weeding at 1-2 months after planting.

7. Weeding: 2-3 times manually, at 30-45 days and 2-3 months later;

or pre-emergence herbicide right after planting and post-emergence

herbicide (using shield) at 2-3 months after planting.

8. Harvest: at 10-12 months; incorporate leaves and stems back into the soil.

9. Intercropping: cassava may be intercropped with two rows of peanut or mung-

bean, with one row of maize or with watermelon, squash etc.

10. Erosion control: plant 1 row of vetiver grass (10-15 cm between plants) along the

contour, with 1 m vertical distance between contour lines. Cut

leaves back to 30 cm above ground at planting of cassava and

at 4-6 months; spread the cut leaves on soil surface between

cassava plants.

210

REFERENCES

Liu Jianpin. 1994. Cassava production research in Hong He district, Yunnan province of China.

(in Chinese)

Qujiang Agricultural Bureau. 1988. Investigation of cassava intercropping systems.

(personal com.)

Tian Yinong and Lee Jun. 1992. Production and development of cassava in Guangxi. Paper

presented at 2nd Chinese Cassava Workshop held Oct 19-24, 1992 at CATAS, Danzhou,

Hainan, China.

Zhang Weite. 1992. Progress in research on cassava agronomy and utilization in China.

Paper presented at 2nd Chinese Cassava Workshop held Oct 19-24, 1992 at CATAS, Danzhou,

Hainan, China.

Zhang Weite. 1996. Summary of experiments on time of planting and harvesting of cassava

conducted at CATAS from 1990-1994. Research on Tropical Crops No. 66:22-27. CATAS,

Danzhou, Hainan, China. (in Chinese)

Zhao Qiguo. 1987. Soil resources in upland areas of the tropical and subtropical zones of China.

Soil: 19:1. (in Chinese)

211

RECENT PROGRESS IN CASSAVA AGRONOMY RESEARCH IN THAILAND

A. Tongglum1, V. Pornpromprathan1 , K. Paisarncharoen2, C. Wongviwatchai2,

C. Sittibusayd, S. Jantawat*, T. Nual-ons and R.H. Howeler*

ABSTRACT

Cassava agronomy research in Thailand during 1994-1996 emphasized mainly erosion

control, soil fertility maintenance and weed control.

Regarding soil erosion control, the planting of cassava in April, at the start of the rainy

season, and harvesting in March resulted in the highest soil loss compared with other planting

dates. Planting at the start of the dry season in Dec and harvesting in Nov produced by far the

highest cassava yield, while soil loss due to erosion was relatively low. Intercropping cassava

with either peanut or pumpkin were found to be the best cropping systems to reduce erosion while

also giving high gross incomes. Cassava planted on contour ridges at closer spacing (1.0x0.6 m)

and with fertilizer application was the most promising package of cultural practices for reducing

erosion and increasing yields.

Soil fertility maintenance through the use of legumes grown for in-situ production of

mulch was studied at Rayong Research Center. The highest yield of cassava, 46.17 t/ha, was

obtained when Crotalaria juncea was planted as a green manure and mulched, followed by

planting cassava, which was then harvested after 18 months. When Canavalia ensiformis was

intercropped with cassava, cut at 2 months and left as a mulch, the yield of cassava, harvested at

12 months, was as high as that obtained with a high rate of chemical fertilizers.

The sequential planting of fertilized Rayong 60 after unfertilized peanut, produced the

highest yield at Kalasin in the Northeast. The cultivar Rayong 5 planted in either Sattahip or

Banbung soils in the East produced a relatively high yield with application of 312 kg/ha of 15-15-

15 together with 100 kg of urea and 78 of KCl/ha. In the Northeast the application of 25-25-25

kg/ha of N, P2Os and K2O produced a significantly higher yield of Kasetsart 50, Rayong 5,

Rayong 60 and Rayong 90 than without fertilizer application.

Research on the long-term effect of soil management on cassava planted continuously for

15 years in Khon Kaen in the Northeast, showed that when cassava was rotated yearly with

sequentially planted peanut and pigeonpea, this could maintain a relative cassava yield of 87 % of

that obtained in the first year. Similarly, the application of soil amendments (lime, rock

phosphates and compost), as well as that of soil amendments with chemical fertilizers, could

reduce the rate of yield decrease over time. However, after 15 years of continuous cropping the

cassava yields in all treatments were lower than those obtained in the first year.

Research on the optimum period of weed control for Rayong 60 and Rayong 90, planted

in both the early and late rainy seasons in the Northeast, indicate that both cultivars need to be

free of weeds at least three months after planting in order to produce high yields.

1 Rayong Field Crops Research Center, Huai Pong, Rayong, Thailand.

2 Khon Kaen Field Crops Research Center, Khon Kaen, Thailand.

3 Soil Science Division, Dept. of Agric, Chatuchak, Bangkok, Thailand.

4 Kasetsart University, Chatuchak, Bangkok, Thailand.

5 Kalasin Field Crops Research Station, Kalasin, Thailand.

6 CIAT Asian Cassava Program, Dept. of Agriculture, Chatuchak, Bangkok, Thailand.

212

The most appropriate weeding method for cassava intercropped with either mungbean

or peanut, was the application at planting time of the pre-emergence herbicide Metolachlor at the

rate of 1.50 kg ai/ha, followed by spot application of the post-emergence herbicide Paraquat at

the rate of 0.50 kg ai/ha whenever necessary.

INTRODUCTION

The Thai cassava breeding programs have recently released several new cultivars

with high yield potential and high starch content, such as Rayong 90 and Rayong 5 and

Kasetsart 50. Thus, the lack of good cultivars is now less of a problem to cassava

farmers. But, appropriate cultural practices are still needed to attain the high yield

potential of these cassava cultivars. Most research on cassava cultural practices has

focused on soil fertility maintenance/improvement in those regions where the crop is

grown continuously, with somewhat less emphasis on appropriate cultural practices to

obtain high yield or income.

Regarding the decline in soil productivity by continuous production of cassava,

research has focussed on erosion control and soil fertility maintenance, while research

on cultural practices for the newly recommended cultivars, such as optimum rate of

fertilizer application and weed control for both monoculture and intercropped cassava,

had also high priority.

Soil Erosion Control

Research on cassava soil conservation has continued since the last Workshop in

1993. Several erosion control experiments were conducted at Rayong Field Crops

Research Center and in Pluakdaeng town of Rayong province, where cassava experiments

were planted on 4-6% slope with highly erodable sandy loam soils.

The objective of these experiments was to quantify the effects of different

planting dates, intercropping and various cultural practices on both soil erosion and

cassava yield. Eroded sediments were collected from plastic covered channels dug along

the lower side of each plot. At monthly intervals the sediments from each plot were

weighed and samples were taken to be dried, in order to determine soil losses on a dry

weight basis. Results of some experiments conducted from 1994 to 1996 are as follows:

1. Effect ofplanting date on cassava yield and soil loss

Table 1 shows the effect of cassava planting date on the root yield and soil loss

in an experiment conducted on 4.2% slope at Rayong Field Crops Research Center. The

cultivar Rayong 90 was planted at six different times of the year; there were no

replications. Rainfall received in the different planting date treatments varied from 777

to 1893 mm, while the total dry soil loss ranged from 7.5 to 12.8 t/ha, and the cassava

yield varied from 15.5 to 46.4 t/ha.

213

Table 1. Effect of cassava planting date on total dry soil loss due to erosion, and on

root yield and starch content of Rayong 90 planted at Rayong Field Crops

Research Center in Rayong, Thailand in 1994/95/96.

Planting date Rainfall Total dry Plants Fresh Root

(Planting-Harvest) received soil loss harvested root yield starch

(mm) (t/ha) (#/ha) (t/ha) (%)

June'94-May'95 777 7.68 9906 15.47 22.3

Aug'94-July'95 997 7.47 9906 24.68 20.0

Oct'94-Sept'95 1265 7.98 9806 38.09 29.2

Dec'94-Nov'95 1749 8.14 8175" 46.44" 28.0

Febr'95-Jan'96 1731 9.65 9038" 39.04" 33.0

April'95-March'96 1893 12.76 9806 37.52 28.6

"Some irrigation was used to ensure establishment during the dry season.

Source: Rayong Field Crops Research Center, Annual Report 1996.

The greater the amount of effective rainfall the higher the soil loss. Cassava

planted in April and harvested in March received the highest amount of rain, which also

caused the greatest soil loss of 12.8 t/ha and resulted in a root yield of 37.5 t/ha. But

the highest root yield of 46.4 t/ha was obtained from planting in Dec and harvesting in

Nov, which also received a lot of rain and caused a considerable amount of soil loss of

8.1 t/ha. Root starch content of Rayong 90 planted at different dates varied from a low

of 20.0 to a high of 33.0% due to different months of harvest. The highest root starch

content of 33% was obtained when Rayong 90 was harvested in the dry month of

January.

2. Use of economic covercrops to increase cassava profitability and reduce erosion

Table 2 shows the results of an experiment on the use of economic covercrops to

increase cassava profitability and reduce erosion, conducted in 1994 and 1995, on sandy

loam soil with 5% slope in Pluakdaeng of Rayong province. Cultivar Rayong 90 was

planted in ten different cropping systems without replication. In the 1994/95 experiment,

the effective rainfall was only 589 mm, compared with 1592 mm in 1995/96.

Nevertheless, soil loss due to erosion was high, ranging from 9.1-35.6 t/ha in 1994/95,

but only 10.6-19.9 t/ha in 1995/96. This is due to very heavy rainfall of 188 mm during

Oct 1994, which caused serious run-off in all plots, but particularly in two plots of sole

cassava and cassava intercropped with watermelon. In both years the results show the

same trend: intercropping cassava with peanut was the most effective in reducing soil loss

due to erosion, while intercropping with cucumber or pumpkin was intermediately

effective. When the intercrops were planted one month after cassava, they were less

effective in reducing erosion.

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Table 2 shows that some cropping systems produced no yield of intercrops due

to either poor establishment or due to competition from cassava. In both years, most

intercrops failed to grow well when planted one month after cassava, but nearly all

established well and yielded better when planted simultaneously with cassava, i.e. peanut,

muskmelon, cucumber and pumpkin yielded 875, 369, 1 19 and 2900 kg/ha, respectively,

while all failed when planted one month after cassava, except pumpkin; but in that case

the yield was only 331 kg/ha. Cassava yields ranged from 4.9-19.1 t/ha. Due to rather

dry weather in 1994/95, with only 589 mm of rainfall in the experimental period, there

was strong competition between crops for soil water. Intercropping cassava with peanut

resulted in the lowest cassava yield of 4.9 t/ha, but this treatment was effective in

reducing soil loss. Nevertheless, total gross income from the various intercropping

systems was generally higher than that of sole cassava. The highest gross income was

obtained from intercropping cassava with pumpkin, both crops planted at the same time.

In the 1995/96 experiment the same trends were observed. When the intercrops

were planted simultaneously with cassava, the intercrops grew well and yielded much

better than when they were planted one month after cassava. Peanut, watermelon,

muskmelon, cucumber and pumpkin yielded 906, 2119, 7125, 5831 and 2900 kg/ha,

respectively, but no intercrops planted one month after cassava could yield anything due

to shading from cassava. Cassava yields ranged from 16.4 to 25.6 t/ha. Intercropping

with peanut reduced cassava yields only about 15% due to less competition for soil

moisture compared with the previous year. Total gross income for the intercropping

systems with simultaneous planting was always higher than that of cassava monoculture.

The highest gross income was obtained from cassava intercropped simultaneously with

muskmelon. The gross income varied from year to year due to variations in the price

of each crop.

Considering both the effectiveness in reducing soil loss and the gross income

obtained, the systems of intercropping cassava with peanut or pumpkin, both planted at

the same time as cassava, appeared the most promising.

3. Cultural practices for erosion control on farmer 's fields

Table 3 shows the results of experiments on different cultural practices to control

erosion in cassava, cv. Rayong 1, conducted on farmers' fields in four locations in

Rayong province in 1994/95 and 1995/96. Each trial compared five "improved

practices" with the "farmer's practice" without replication. In all locations the soil had

a light sandy loam texture with slopes ranging from 4.3 to 6.7%. The overall average

soil loss due to erosion in the different locations in 1994/95 ranged from 5. 1 to 43. 1 t/ha,

and in 1995/96 from 7.2 to 18.0 t/ha. In both years the soil loss depended on the rainfall

and the slope at each location, except that in Nongrai soil loss was very low because of

natural terrace formation as a result of land preparation in the same trial conducted

during two previous years.

216

Table 3. Slope and rainfall as well as the average dry soil loss due to erosion in

on-farm erosion control trials conducted in four locations in Rayong

province of Thailand in 1994/95 and 1995/96.

Slope Rainfall #Rainy Dry soil loss

Location (%) (mm) days (t/ha)

1994/95

1 . DLD Center, Rayong 6.05 1071 80 43.10

2. Nongrai, Rayong 4.80 890 58 5.10

3. Nongbua I, Rayong 5.10 832 58 30.51

4. Nongbua II, Rayong 4.30 831 58 27.24

1995/96

1 . DLD Center, Rayong 6.05 1585 107 17.88

2. Nongrai, Rayong 4.80 1325 96 7.19

3. Mabka I, Rayong 6.70 1475 97 16.98

4. Mabka II, Rayong 5.50 1475 97 17.99

Source: Rayong Field Crops Research Center, Annual Reports 1995 and 1996.

The actual "farmer's practice" varied from site to site each year. In the 1994/95

experiments, three of the four farmers planted cassava on contour ridges and all applied

15-15-15 fertilizers at a rate of about 206 kg/ha. In the 1995/96 experiment all farmers

planted cassava on contour ridges and again applied 15-15-15 fertilizer at a rate of 206

kg/ha.

Table 4 shows the effect of different cultural practices on cassava yield and soil

loss in the 1994/95 and 1995/96 experiments. In the 1994/95 experiments, the average

dry soil loss caused by different cultural practices ranged from 20.5 to 38.6 t/ha, while

the cassava yields ranged from 11.7 to 18.8 t/ha. Best results were obtained from

cassava planted at 0.8 x 0.8 m on contour ridges and with fertilizer application; this

produced the highest cassava yield of 18.8 t/ha with the least soil loss of 20.5 t/ha.

There were some questionable data on soil erosion at Nongbua II during the first month

(July) with rainfall as high as 319 mm in 14 days; this heavy rain broke some contour

ridges in treatment 3, thus causing higher than normal levels of erosion. To solve the

problems of runoff water entering the plots from fields above, it was suggested to

partially dig into the soil narrow strips of zinc sheet along the upper side of the plots.

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In the 1995/96 experiment, soil loss from different cultural practices ranged from

8.6 to 26.7 t/ha and cassava yields ranged from 1 1.5 to 22.8 t/ha. The best results were

again obtained from cassava planted at either 0.8x0.8 m or 1 .0x0.6 m on contour ridges

and with fertilizer application; those treatments resulted in the highest cassava yields of

22.8 and 21 .7 t/ha, with relatively low soil loss of 10.2 and 8.6 t/ha, respectively. When

cassava was planted without contour ridges the soil loss was higher, ranging from 15.3

to 26.7 t/ha. The results of these two years of experiments show clearly that contour

ridge planting can reduce soil erosion in cassava fields while increasing cassava yields;

they also indicate that fertilizer application will generally increase yields, but contrary to

previous results obtained, it also increased erosion.

Soil Fertility Maintenance

Several studies on the maintenance of soil fertility in cassava fields through the

use of green manures, chemical fertilizers or soil amendments were conducted in the East

and Northeast of Thailand, where cassava is the major upland crop. The overall

objective was to maintain or improve the soil fertility in fields of continuously grown

cassava in order to sustain a high long-term productivity.

Results of a study on soil fertility maintenance through the use of green manures

conducted from 1988 to 1994 at Pluakdaeng in Rayong province have shown that legume

species such as Crotalaria juncea, Mucuna fospeada and Canavalia ensiformis, when

planted as green manures, could improve soil fertility and increase cassava yields

(Tongglum et at., 1992; Sittibusaya et at., 1995). In the 1991/92 experiment these

legume species produced 7.31, 4.83 and 5.17 t/ha of above-ground dry matter,

respectively, which contained 123, 157 and 136 kg/ha of total N. The yield of eassava

increased from 3.6 t/ha without green manure to 7.7, 7.0 and 6.0 t/ha when these green

manures were used.

It was found that incorporating the green manures into the soil had no significant

effect on cassava yield compared to leaving the cut green manures as a mulch on the soil

surface, resulting in average yields of 8.3 and 7.4 t/ha, respectively (RFCRC, 1994).

/. Effect of green manures grown as in-situ production of mulch on cassava yield

In 1994/95 a new study was conducted at Rayong Field Crops Research Center

with the objective of determining the most appropriate management of green manures

grown for in-situ production of mulch, which would produce high yields of cassava and

maintain soil productivity. Rayong 90 was used as the test variety in the experiment and

four species of green manures, i.e. Crotalaria juncea, Canavalia ensiformis, pigeonpea

ICP 8094 and Mucuna fospeada, were planted, in three systems: 1. simultaneously

intercropped in cassava and cut off and mulched at 2 MAP; 2. interplanted into 6-7

month old cassava and mulched before the next cassava planting; or 3. planted as a

normal green manure, cut and incorporated before planting of cassava, which would then

219

be harvested at 18 months. In addition, in two treatments cassava was intercropped with

cassava which was either pulled up or cut off at 2 months and mulched. These various

green manure treatments were compared with two treatments of sole cassava with

fertilizer 13-13-21 applied at rates of either 156.25 or 468.75 kg/ha.

Table 5 shows that among the green manures Crotalariajuncea always produced

the highest above-ground dry matter, ranging from 1.44 to 9.89 t/ha, which contained

39.9 to 262. 1 kg/ha of total N. Pigeonpea was the next most productive green manure,

followed by Canavalia ensiformis, while Mucuna fospeada failed to germinate.

Crotalaria juncea, Canavalia ensiformis and pigeon pea planted as intercrops in a 6-7

month old cassava stand, produced higher above-ground dry matter, which contained also

more N than other management treatments, since these green manures were left to grow

and were cut only after 4.5 months (at cassava harvest).

Cassava yields ranged from 8.75 to 46.17 t/ha. Very high cassava yields,

ranging from 38.8 to 46.2 t/ha were obtained when cassava was harvested at 18 months

for a 2-year cycle. The highest cassava yield of 46.2 t/ha was obtained when Crotalaria

juncea was planted as a green manure and then cut and mulched before planting cassava,

which was then harvested at 18 months. Of those treatments harvested at 12 months,

lowest yields were obtained when cassava was intercropped with cassava, which was cut

at 2 months at 30 cm above ground level to serve as mulch, as well as the interplanting

of Crotalariajuncea into a 6-7 month old cassava stand, due to the strong competition

from the intercropped cassava or Crotalaria. The other treatments produced cassava

yields ranging from 15.9 to 23.8 t/ha, which were not significantly different from the

treatment without green manure but with high fertilizer application. The intercropped

Crotalaria juncea planted at 6-7 MAP cassava exerted a strong competitive effect on

cassava, resulting in a yield reduction; intercropping cassava with cassava also reduced

yields, not only by the competitive effect but also because the cassava intercrop produced

the lowest amount of mulching material. According to the objective, the intercrop

residues were left as mulch for the next cassava crop. However, the results in Table 5

show only the competitive effect on the yield of cassava in the first year, but the residues

of these green manures are to be mulched for the next cassava crop, which may show a

positive effect on cassava yield in the second year. With regard to the usual harvest of

cassava at 12 months, when Canavalia ensiformis was planted as an intercrop at the same

time as cassava, cut at 2 months and left as mulch, this increased the cassava yield to

26.9 t/ha, nearly as high as that of sole cassava with a much higher fertilizer rate of 469

kg/ha of 13-13-21.

220

Table 5. The effect of green manures grown as in-situ production of mulch on the yield of

cassava grown at RFCRC in Rayong, Thailand in 1994/95/96.

Treatment

1. Cassava+Fert. 13-13-21 (156 kg/ha)

2. Cassava+Fert. 13-13-21 (469 kg/ha)

3. Cassava + Crotalaria juncea (cut at 2 months)

4. Cassava + Canavalia ensiformis (cut at 2 months)

5. Cassava + Pigeon pea ICP 8094 (cut at 2 months)

6. Cassava +Mucuna fospeada (cut at 2 months)

7. Cassava+cassava (pulled out at 2 months)

8. Cassava +cassava (cut at 2 months)

9. Cassava + Crotalaria juncea (6-7 months)

10. Cassava + Canavalia ensiformis (6-7 months)

11. Cassava + Pigeon pea ICP 8094 (6-7 months)

12. Cassava+Mucuna fospeada (6-7 months)

13. Crotalaria juncea-Cassava(18 months)

14. Canavalia ensiformis-Cassava(\8 months)

15. Pigeon pea ICP 8094-Cassava( 1 8 months)

16. Mucuna fospeada-C&ssa\&(\8 months)

LSD(O.Ol) - - - 13.45

F-test - - NS **

CV(%) - - 7.28 23.88

Note: Treatments 9-12: green manures were cut at 4.5 months (at harvest of cassava)

Treatments 6, 12 and 16: Mucuna fospeada failed due to poor germination and stem rot

Treatments 3-16: 156 kg/ha of 13-13-21 were applied to cassava

Treatments 1-12: cassava was harvested at 12 months

Treatments 13- 16: cassava was harvested at 18 months

Green Total Plants Fresh

manures N harvested root

(t/ha) (kg/ha) (#/ha) yield

(t/ha)

- . 8613 17.56

- - 9169 29.78

1.92 44.75 8888 23.75

0.94 20.13 9025 26.94

1.09 27.00 8613 21.39

- - 9444 20.28

0.36 11.75 8750 18.25

0.09 1.69 8613 12.00

9.89 262.13 8888 8.75

1.54 36.63 9306 22.83

8.92 221.69 9725 15.86

- - 9025 17.25

1.44 39.94 8888 46.17

0.93 18.38 9725 42.98

1.05 25.63 8056 38.81

- . 9306 38.86


221

Table 6. Soil pH and organic matter(OM), before planting and after harvest of cassava in

different treatments of green manures at RFCRC, Rayong, Thailand in 1994/95/96.

Treatments' '

Before plantingAfter harvest

pH %OM pH %OM

1. Cassava + Fert. 13- 13-21 (156 kg/ha)

2. Cassava + Fert. 13-13-21 (469 kg/ha)

3. Cassava + Crotalaria juncea (cut at 2 months)

4. Cassava + Canavalia ensiformis (cut at 2 months)

5. Cassava + Pigeon pea ICP 8094 (cut at 2 months)

6. Cassava + Mucuna fospeada (cut at 2 monthsa)

7. Cassava + cassava (pulled out at 2 months)

8. Cassava + cassava (cut at 2 months)

9. Cassava + Crotalaria juncea (planted at 6-7 months)

10. Cassava + Canavalia ensiformis (planted at 6-7 months)

11. Cassava + Pigeon pea ICP8094 (planted at 6-7 months)

12. Cassava + Mucuna fospeada (planted at 6-7 months)

13. Crotalaria juncea green manure-Cassava (18 months)

14. Canavalia ensiformis green manure-Cassava (18 months)

15. Pigeon pea ICP 8094 green manure-Cassava (18 months)

16. Mucuna fospeada green manure-Cassava (18 months)

5.60 0.51 5.20 0.54

5.60 0.46 5.00 0.52

5.90 0.49 5.20 0.49

5.70 0.53 5.40 0.56

5.60 0.54 5.20 0.61

5.50 0.59 5.00 0.63

5.60 0.44 5.30 0.52

5.60 0.45 5.30 0.45

5.70 0.48 5.20 0.47

5.80 0.43 5.20 0.50

5.70 0.46 5.10 0.63

5.60 0.56 5.10 0.65

5.60 0.44 4.90 0.41

5.50 0.48 5.20 0.59

5.80 0.56 5.10 0.59

5.60 0.57 5.00 0.47

"Treatments 3-16: 156 kg/ha of 13-13-21 were applied to cassava


Soil chemical analysis data, shown in Table 6, indicate a decreasing trend in soil

pH both with and without green manures, as compared to the soil analysis before

planting. Although Crotalaria juncea had the highest above-ground dry matter

production in all patterns of green manure management, this did not result in an increase

in soil OM. However, these results are still very preliminary and it will take a few years

to confirm the effect of green manures on the yield of cassava and on soil fertility.

2. Effect ofplant spacing and fertilization on the yield of Rayong 5

In 1995/96, a study on the effect of plant spacing and rate of fertilizer

application was conducted in Banbung and Sattahip soil series of Rayong province in the

eastern part of Thailand. The objective was to determine the optimum spacing and rate

of fertilizer application for the new Rayong 5 cultivar. Table 7 shows that plant spacing

at 0.8x0.8 or 1.0x1.0 m had no significant effect on either yield or starch content of

Rayong 5 in both Banbung and Sattahip soil series. This suggests that Rayong 5 could

be planted at any plant spacings corresponding to a plant population ranging from 10,000

to 15,625 plants/ha in both soils.

222

Table 7. The effect of plant spacings and rate of fertilizer application on the yield

and starch content of Rayong 5 planted in Banbung and Sattahip soil

series, Rayong, Thailand in 1995/96.

Banbung soil series

Fresh root Starch

yield content

(t/ha) (%)

Sattahip soil series

Fresh rootStarch

yield content

(t/ha) (%)

Spacings(S)

0.8x0.8 m

1.0x1.0 m

28.50

29.00

18.03

17.85

33.25

29.94

22.04

21.35

F-test(S) NS NS NS NS

Rates of fertilizer(R)

N-PX)<-K,Q(kg/ha)

0-0-0

46-23-46

92-46-92

138-69-138

184-92-184

F-test(R)

F-test(SxR)

CV(%)

18.00c 14.50b 23.06c 21.13

26.06bc 17.23ab 27.25c 22.00

30.06b 19.32a 35.75b 22.57

32.69ab 18.98a 34.19b 21.20

37.00a 19.67a 40.56a 21.57

* * *NS

NS NS NS NS

25.92 15.26 14.71 5.47


The effect of chemical fertilizers applied in the ratio 2:1:2 of N:P205:K2O by

using combinations of compound fertilizer 15-15-15 with urea and KC1 at four different

rates, in comparison with the non-fertilized check, is shown in Table 7. In Banbung soil

series, there was a significant response to fertilizer rates both in terms of cassava yield

and starch content. Application of fertilizers at the rate of 92 kg N, 46 P2O5 and 92

K2O/ha produced a significantly higher root yield of 30. 1 t/ha than did the check without

fertilizer (18.0 t/ha). The highest yield of Rayong 5 was obtained with the application

of 184 kg N, 92 P2O5 and 184 K2O/ha applied as 625 kg/ha of 15-15-15 supplimented

with 200 kg of urea and 156 kg of KCl/ha, which produced a yield of 37.0 t/ha. The

treatment without fertilizer application also resulted in the lowest starch content of

Rayong 5 at only 14.5%, compared to 19.7% when the highest rate of fertilizers was

223

applied. The results indicate that Rayong 5 cultivar, planted in Banking soil series needs

application of fertilizer 15-15-15 at least at the rate of 312 kg/ha with 100 kg of urea and

78 kg of KCl/ha to produce a high root yield and starch content.

In the Sattahip soil series, the response to fertilizers was also significant in terms

of root yield. The intermediate rate of 92 kg N, 46 P205 and 92 K20/ha, applied as 312

kg/ha of 15-15-15 with 100 kg of urea and 78 kg of KCl/ha, produced a significantly

higher root yield of 35.8 t/ha than the check without fertilizer (23. 1 t/ha). The highest

root yield of Rayong 5 was again obtained with the highest rate of applied fertilizers, i.e.

625 kg/ha of 15-15-15 with 200 kg of urea and 156 kg of KCl/ha, which produced a

yield of 40.56 t/ha. But, fertilizer application did not result in any significant difference

in starch content of Rayong 5, which ranged from 21.1 to 22.6%. The results indicate

that Rayong 5 planted in Sattahip soil series also needs the same application of fertilizer

15-15-15 at least at the rate of 312 kg/ha supplimented with 100 kg/ha of urea and 78

kg/ha of KC1 to produce a high root yield and starch content.

3. Use of legumes as green manures to sustain the productivity of cassava at Kalasin]

A study on the use of grain legumes as green manures to sustain the productivity

of Rayong 60 was conducted in 1994/95 in Kalasin province in the northeast of Thailand,

where cassava has been a major field crop.

The experiment consisted of eight cassava-based cropping systems, in which

three grain legume species, i.e. cowpea for grain, cowpea for green pods and peanut

were planted in rotation with cassava, cv. Rayong 60. Leaving the land in fallow before

planting cassava was another treatment used for comparison; in this case fertilizers were

not applied or were applied as 12-24-12 at a rate of 156 kg/ha. In the legume rotation

treatments either 15-15-15 fertilizer at the rate of 125 kg/ha was applied to cassava but

without fertilizer for the legume, or 12-24-12 fertilizer at the rate of 156 kg/ha was

applied to the legumes without fertilization of cassava. Legumes were planted in June

and harvested in Sept. Cassava was planted in Oct and harvested in May of each year

on Korat soil series with pH 5.54, 0.60% OM, 110 ppm available P and 46 ppm

exchangeable K.

The results of the first year experiment, shown in Table 8, indicate that with

fertilizer application, all grain legumes produced higher yields (863-2300 kg/ha) than

without fertilizer (663-1938 kg/ha). Cassava yields differed significantly depending on

the various cropping systems. Cassava yields tended to be significantly higher when

fertilizers were applied to cassava rather than to the preceding legume. When fertilizers

were applied to cassava there was no significant effect of the preceding grain legume, but

when no fertilizers were applied to cassava, yields were significantly higher after the

grain legumes than after bare fallow. This indicates that the residual effect of fertilized

legumes could help maintain soil fertility for cassava production. The highest yield of

22.5 t/ha was obtained from planting fertilized cassava after unfertilized peanut. The

224

root starch contents of cassava in the various cropping systems were not significantly

different among treatments. The experiment needs to be repeated several years with soil

analysis data to be able to conclude whether any of these cropping systems improves the

long-term sustainability of cassava production in these poor northeastern soils.

Table 8. The effect of several cassava-grain legume rotation systems on the yield and

starch content of cassava, Rayong 60, as well as the yields of the grain

legumes grown at Kalasin, Thailand in 1994/95.

Cropping systems"

Grain Cassava Cassava

legumes plants fresh root Starch

yield harvested yield content

(kg/ha) (#/ha) (t/ha) (%)

863 9256 16.38b 20.53

663 8775 19.13ab 22.68

1750 8938 18.06b 21.14

1000 9063 22.50a 23.70

2300 9125 18.56b 20.80

1938 8875 19.38ab 22.80

- 8750 15.38c 20.40

- 9125 18.88ab 20.55

- NS*

NS

- 10.50 17.50 12.60

1. Cowpea (Seed) + F -Cassava-F

2. Cowpea (Seed)-F -Cassava+F

3. Peanut + F -Cassava-F

4. Peanut-F -Cassava + F

5. Green Cowpea+F -Cassava-F

6. Green Cowpea-F -Cassava + F

7. Fallow -Cassava-F

8. Fallow -Cassava + F

F-test

CV(%)

" +F = with fertilizer ;-F = without fertilizer

156 kg/ha of 12-24-12 were applied to legumes in treatments 1, 3 and 5

125 kg/ha of 15-15-15 were applied to cassava in treatments 2, 4, 6 and 8

Source: Khon Kaen Field Crops Research Center, Annual Report 1995.

4. The fertilization of new high-yielding cassava varieties

In 1994/95 a study on the effect of chemical fertilizers on the yields and starch

contents of newly released cassava varieties was conducted at Udon Thani and Khon

Kaen provinces in the northeast of Thailand. Three cultivars were tested in each

location, i.e. Kasetsart 50, Rayong 5 and Rayong 60 tested in Udon Thani, and Kasetsart

50, Rayong 90 and Rayong 60 in Khon Kaen.

The results shown in Table 9 indicate that in Udon Thani the yields of the three

varieties were not significantly different, ranging from 28.5 to 34. 1 t/ha. The root starch

content of Rayong 60 was significantly lower than that of Kasetsart 50, and slightly but

not significantly lower than that of Rayong 5. There were also no significant effects of

225

rates of chemical fertilizer in terms of yield and starch content. Nevertheless, there was

an increasing trend in root yield with increasing rates of chemical fertilizers applied: at

higher rates all cassava cultivars tended to produce higher yields.

Table 9. The effect of chemical fertilizers on the yield and starch content of three

cassava cultivars grown in Udon Thani and Khon Kaen, Thailand in

1994/95.

Udon Thani Khon Kaen

Fresh root Starch Fresh root Starch

yield content yield content

Cultivars(C)

(t/ha) (%) (t/ha) (%)

Kasetsart 50 33.05 25.0a 16.10a 22.6

Rayong 90 - - 10.49b 22.6

Rayong 5 34.07 23.0ab -

Rayong 60 28.51 21.0b 8.36b 17.4

F-test(C) NS*

* NS

Rates of fertilizer(R):kg/ha

0-0-0 24.44 23.0 8.36b 22.4

25-25-25 30.24 22.0 12.74a 21.9

50-50-50 35.78 23.0 13.33a 20.6

75-75-75 37.03 23.0 12.16a 18.4

F-test(R) NS NS * NS

F-test(CxR) NS NS NS NS

CV(%) 24.8 8.03 28.50 13.20


At Khon Kaen, the yields were much lower, but the yield of Kasetsart 50 was

significantly higher those of Rayong 90 and Rayong 60. There were no significant

differences in root starch content between these cultivars.

On average, chemical fertilizer, applied at the rate of 25-25-25 kg/ha of N, P205

and K2O, produced significantly higher yields than without fertilizer application, which

produced only 8.36 t/ha. At higher rates of fertilizer application the effect on cassava

yields was not significant. Although there was a trend of decreasing starch content with

increasing rates of fertilizers, differences were not statistically significant.

226

There were no significant interactions between cultivars and rates of chemical

fertilizer on yield and starch content at both Udon Thani and Khon Kaen.

5. Long-term effect of cropping system on cassava productivity in the Northeast

Since 1980, a semi-demonstration study on the long-term effect of various soil

management treatments on cassava production has been conducted at Khon Kaen Field

Crops Research Center in the Northeast of Thailand.

The cropping systems of sole cassava, cassava intercropped with peanut and

cassava rotated with sequentially planted peanut and pigeonpea were tested with and

without fertilization and with and without soil amendments. The objective of the trial

was to determine the most appropriate soil management system to maintain soil fertility

and sustain high cassava yields. Rayong 1 was used as the test cultivar in this long-term

experiment.

Table 10 shows the cassava yields obtained in the different cropping systems

with various soil management treatments. In the first year (1980) sole cassava produced

the highest average yield of 27.4 t/ha, compared to 24.0 t/ha for cassava rotated with

peanut-pigeon pea, and 25.5 t/ha for cassava intercropped with peanut. During the first

year, cassava could still produce a rather high average yield of 25.6 t/ha without any

fertilizers or soil amendments. When only fertilizers were applied, cassava produced the

highest yield of 28.7 t/ha, or 12% higher than without fertilizers, while soil amendments

slightly decreased cassava yields, both in the absence and presence of chemical fertilizers.

In the 15th year (1994), the highest average cassava yield of 20.9 t/ha was

obtained when cassava had been rotated with sequentially planted peanut and pigeon pea,

while the continuous planting of sole cassava produced a lower yield of 16.8 t/ha. The

lowest cassava yield of 12.9 t/ha was obtained when cassava had been intercropped with

peanut during the past 15 years, probably due to competition from the intercropped

peanut. Considering the soil management effect on cassava yields in the 15th year, the

lowest average yield at 11.2 t/ha was obtained in the check plots without fertilizers or

soil amendments. When only chemical fertilizers had been applied, cassava produced the

highest yield of 20.0 t/ha, or 78% higher than without fertilizers. Soil amendments alone

or in combination with chemical fertilizers resulted in yields of 17.5 and 18.7 t/ha, or

56 and 67%, respectively, higher than the check plots.

When the average yields in the 15th year are compared to those of the first year,

it is clear that neither cropping systems nor soil management treatments could maintain

or increase cassava yields. The overall average yield of all cropping systems and soil

management treatments in the 15th year was only 66% of that of the the first year. Only

the rotation of cassava with sequentially planted peanut and pigeon pea could maintain

a relatively high yield of cassava, corresponding to 87% of the yield obtained with the

same cropping system in the first year. Among soil management treatments, the check

plots without any fertilizers or soil amendments produced the lowest relative yield of

227

44% of that obtained in the first year. Only the treatments of cassava rotated with

peanut-pigeonpea and with either chemical fertilizers alone or in combination with soil

amendments could produce-high cassava yields in the 15th year that were comparable to

those obtained in the first year.

Table 10. A semi-demonstration study on the long-term effect of soil management

on the yield (t/ha) of cassava grown at Khon Kaen, Thailand from 1980

to 1994.

Cropping system

Soil management

1* Year(1980)

Check Fertilize!•" Soil Fertilizer + Soil

amendment2' amendment3' Average

Cassava 30.13

27.88

18.81

32.38

26.81

27.00

20.38

18.63

27.31

26.63

22.88

28.81

27.38

24.05

25.48

Cassava/Peanut-Pigeon

Cassava+ Peanut5)

pea4)

Average of 1st year 25.61 28.73 22.11 26.11 25.64

15th Year(1994)

Cassava 8.81 21.68

24.50

13.81

19.81

20.25

12.56

16.87

23.12

16.12

16.79

20.88

12.91

Cassava/Peanut-Pigeon

Cassava+ Peanut5*

pea4) 15.68

9.18

Average of 15th year

Relative to l"year(%)

11.22

44

19.99 17.54

70 79

18.70

72

16.86

66

" Applied 50-50-50 kg/ha of N-P205-K20 to cassava

or 18.75-56.25-37.50 kg/ha of N-P205-K20 to peanut in crop rotation treatment4'

% Applied 1250 kg/ha of lime and rock phosphate(3%P205)with 18.75 t/ha of munucipal

compostin the 1st, 5th, 9th, and 13th year(1980, 1984, 1988 and 1992)

3' l)+2).

4) Cassava and peanut-pigeon pea were planted in alternate years

After the harvest of sequentially planted legumes, the residues were incorporated

into the soil before the following years' planting of cassava.

51 2 rows of peanut were intercropped between cassava rows.

After harvest of peanut the residue was used as mulch.

Source: Khon Kaen Field Crops Research Center, Annual Reports 1992 and 1995.

Weed Control

Weeds are known as a major problem, causing serious cassava yield reductions.

Nowadays, labor for weed control is hard to find and the cost of manual weeding is

228

getting higher and higher each year. To solve these problems several studies were

conducted at Khon Kaen and Rayong Research Centers during two years from 1993 to

1995 to determine the best methods and times of weed control in cassava.

1. Weed control for three cassava cultivars

Experiments on weed control for cassava were conducted in 1993/94 at Khon

Kaen Field Crops Research Center in the northeast of Thailand. Rayong 1, Rayong 60

and Rayong 90 cultivars were planted in both the early and late rainy seasons. Plots

were maintained weed free for either 0 (non-weeded check), 2, 3 or 4 MAP by manual

weeding, compared to a typical "farmer" practice of manual weeding only at 2 MAP and

with no fertilizer application. The objective was to determine the optimum period for

controlling weeds, which would produce high yields when cassava was planted in either

the early or late rainy season.

Table 11 shows that yields of Rayong 1, Rayong 60 and Rayong 90 cultivars,

averaged over two years and two seasons, were not significantly different, ranging from

17.6 to 20.2 t/ha. There were no significant interactions between cultivars and weed-free

periods when cassava was planted in either the early or late rainy seasons. However,

weed control treatments produced highly significant differences in yield (averaged over

cultivars and seasons/years), ranging from 20.1 to 23.4 t/ha, compared to only 7.7 t/ha

in the non-weeded check. The results indicate that weed control is extremely important

during the first two months after planting, but that weed control beyond 2 MAP did not

significantly increase yields any further. The highest cassava yields were obtained when

plots were maintained weed-free for 3 MAP. Thus, when cassava was planted in either

early or late rainy season these three cassava cultivars needed to be free of weeds about

2-3 months after planting to produce highest yields.

2. Weed controlfor cassava intercropped with mungbean and peanut

Experiments on weed control for cassava intercropped with mungbean or peanut

were conducted during two years (1994-1996) at Rayong Field Crops Research Center

in the East of Thailand. The objective of the experiment was to determine the most

appropriate methods of weed control in cassava-legume intercropping systems, which

would produce high yields of intercrops and cassava, resulting in a high income.

Cassava, cv. Rayong 90, was planted in three cropping systems, i.e. sole cassava,

intercropped with mungbean or with peanut. Four different methods of weed control

involved various combinations of pre-emergence herbicide Metolachlor (1.5 kg ai/ha, a

post-emergence herbicide Paraquat (0.5 kg ai/ha), and manual weeding. Weeds were

controlled by either Metolachlor (alone), Metolachlor followed by hand weeding or

Metolachlor followed by application of Paraquat, as compared to hand weeding alone.

In sole crops of peanut and mungbean, weeds were controlled by either Metolachlor

(1.50 kg ai/ha) or by hand weeding; these functioned as check plots of the intercrops.

229

Table 11. Effect of weed control on yield (t/ha) of Rayong 1, Rayong 60 and Rayong

90 planted in the early and late rainy seasons at Khon Kaen, Thailand

in 1993/94 and 1994/95.

1993/94 1994/95 Average 2 years

Average

Cultivars(C)

ER LR ER LR ER LR 2 seasons

Rayong 1 28.33 19.53 10.86 17.23 20.97 18.38 19.67

Rayong 60 23.33 27.68 15.11 14.59 19.22 21.13 20.18

Rayong 90 25.03 21.88 11.33 12.25 18.18 17.06 17.62

F-test(C) NS* *

NS NS*

NS

Weed-free period(W)

0 month (check) 2.61 13.48 4.49 5.63 5.83 9.56 7.69

2 months 31.98 26.43 16.71 15.52 24.34 20.98 22.66

3 months 34.71 26.03 13.84 19.20 24.28 22.61 23.44

4 months 31.47 24.96 13.73 17.54 22.59 21.25 21.93

"Farmer" practice" 27.07 24.25 13.39 15.54 20.23 19.89 20.06

LSD(0.05)for W 6.73 7.38 4.97 5.82 5.51 4.70 3.56

F-test(W)** ** ** ** ** ** **

F-test(CxW) NS NS**

NS NS NS NS

CV(%) 27.00 29.60 41.40 40.70 42.60 37.40 39.90

""Farmer" practice = manual weed control at 2 months with no fertilizers applied


Table 12 shows that the yields of mungbean, both when grown as intercrops and

as sole crops in 1994/95 and 1995/96 were not significantly affected by different weeding

methods; yields ranged from 319 to 450 kg/ha in 1994 and from 175 to 231 kg/ha in

1995. The same results were obtained with peanut, the yield of which ranged from 419

to 556 kg/ha in 1994, and from 300 to 356 kg/ha in 1995. The results indicate that

neither cassava competition nor weeding method were significantly affecting the yields

of the two legumes.

Table 13 shows the cassava yields in three different cropping systems as affected

by different weeding methods. In 1994/95, there was no significant effect of cropping

system on cassava yield, but the highest yield of 16.9 t/ha was obtained when cassava

was intercropped with peanut. However, this same treatment resulted in a significantly

lower cassava yield in 1995/96. Cropping systems had no significant effect on cassava

230

root starch content in either year. There were also no interaction effects between

cropping systems and weeding methods, both in terms of cassava yield and starch

content. However, the effects of different weeding methods on cassava yields were

highly significant in both years, with the lowest yields of 7. 14 and 7.46 t/ha obtained in

1994/95 and 1995/96, respectively, when weeds were controlled by application of

Metolachlor only at planting. Thus, in that treatment cassava yields were significantly

depressed by weed competition. The other three weeding methods resulted in yields that

were not significantly different, ranging from 14.4 to 18.4 t/ha in 1994/95 and from 1 1 .5

to 14.2 t/ha in 1995/96. The highest cassava yields of 18.4 t/ha in 1994/95 and 13.8 t/ha

in 1995/96 were obtained with application of Metolachlor at 1.50 kg ai/ha, followed by

two manual weedings. The weeding methods caused no significant differences in cassava

root starch contents.

The net income obtained with the various cropping systems and methods of weed

control are shown in Table 14. With respect to weeding methods in each cropping

system the highest net income in the 1994/95 experiment was obtained by intercropping

cassava with peanut (1 153 US $/ha) or when grown as a monocrop (832 US $/ha), when

weeds in both cropping systems were controlled by application of Metolachlor followed

by two manual weedings. In contrast, the highest net income of 938 US $/ha in the

cassava-mungbean intercropping system was obtained when weeds were controlled by

application of Metolachlor followed by two spot applications of Paraquat.

In the 1995/96 experiment (Table 13), there was a highly significant competitive

effect when cassava was intercropped with peanut, resulting in the lowest yield at 10.2

t/ha. The yield of cassava intercropped with mungbean was not significantly different

from that of sole cassava, since mungbean has a shorter crop duration and thus causes

less competition than peanut. Root starch contents of cassava were not significantly

different in all cropping systems. There were again no interaction effects between

cropping systems and weeding methods, both in terms of yield and starch content.

However, the different weeding methods caused highly significant differences in cassava

yields, with the lowest yield of 7.5 t/ha obtained when weeds were controlled by only

one application of Metolachlor at planting. The highest cassava yield of 14.2 t/ha was

obtained with three manual weedings. The application of Metolachlor followed by hand

weeding was not significantly different from hand weeding alone. Weeding methods had

no significant effect on root starch content except that the application of Metolachlor

alone resulted in a higher starch content than hand weeding alone. Since the last hand

weeding was done at 2.5 months before the cassava harvest, the mulch of dead weeds

might have increased soil moisture causing a reduction in starch content.

231

Table 12. Effect of different weed control methods on the yields of mungbean and

peanut, grown either intercropped in cassava or as a monocrop in Rayong

Field Crops Research Center, Rayong, Thailand in 1994/95 and 1995/96.

Mungbean" Peanut2)

Treatment 1994/95 1995/96 1994/95 1995/96

Intercropped with cassava

(kg/ha) (kg/ha) (kg/ha) (kg/ha)

1. Metholachlor (1.50 kg ai/ha) 325 175 419 300


+hand weeding


+ Paraquat (0.50 kg ai/ha)

4. Hand weeding 319 206 506 356

Sole crops

5. Hand weeding 356 206 494 331


F-test NS NS NS NS

CV (%) 29.72 10.25 20.29 17.72

"Yield of dry grain

2)Yield of dry pods


Table 14 shows that the highest net incomes of 314 and 269 US $/ha in the

intercropping systems with peanut and mungbean were obtained when weeds were

controlled by application of Metolachlor followed by three spot applications of Paraquat.

The highest net income of 273 US$/ha in sole cassava was obtained when weeds were

controlled by application of Metolachlor only at planting.

The results from both years show some contrasting effects of cropping systems

and weed control methods on cassava yields and net income, depending on the season of

planting in each year. With the variation in the prices of the various crops, in rainfall

and thus in weed condition and weeding costs, the net incomes varied from year to year.

Nevertheless, in both years the best method for controlling weeds when cassava was

intercropped with mungbean was the application of pre-emergence herbicide Metolachlor

at planting, followed by spot treatments with the post-emergence herbicide Paraquat. The

experiment will be repeated in 1996/97 to refine the results.

232

Table 13. The effect of three cropping systems and four methods of weed control on

the yield and starch content of Rayong 90 planted at Rayong Field Crops

Research Center, Rayong, Thailand in 1994/95 and 1995/96.

1994/95 1995/96

Root yield Starch Root yield Starch

Cropping system(C)

(t/ha) (%) (t/ha) (%)

Intercropped with mungbean 11.46 22.07 12.18ab 24.74

Intercropped with peanut 16.90 23.77 10.18b 24.69

Sole cassava 13.74 23.28 12.96a 24.69

F-test(C) NS NS**

NS

CV (%) a: 35.61 7.25 9.63 8.63

Weeding methods(W)

1. Metholachlor (1.50 kg ai/ha) 7.14b 23.38 7.46c 26.21a

2. Metholachlor (1.50 kg ai/ha) 18.39a 23.24 13.83ab 24.59ab

+ hand weeding

3. Metholachlor (1.50 kg ai/ha) 16.17a 23.00 1 1 .54b 24.50ab

4. Hand weeding 14.43ab 22.53 14.24a 23.53b

F-test(W)**

NS** **

F-test(CxW) NS NS NS NS

CV (%)b: 39.61 7.05 14.90 5.44


Recommended Cultural Practices

Table 15 shows the currently recommended varieties and their major

characteristics, as well as the recommended cultural practices, based on research results

obtained by various research institutes in Thailand during the past 30 years.

FUTURE RESEARCH PRIORITIES

Studies on the effect of cassava production on soil fertility, and studies on soil

conservation using combinations of cropping systems and soil management practices for

erosion control and fertility maintenance, so as to sustain high cassava yields in the major

cassava producing areas, will remain of high priority. Studies on optimum cultural

233

practices, ie. rate, time and method of fertilizer application, weed control for various

cassava-based cropping systems and for the newly recommended cultivars, will also

continue.

Table 14. The effect of three cassava-based cropping systems and four methods of weed

control on the total net income obtained at Rayong Field Crops Research Center,

Rayong, Thailand in 1994/95 and 1995/%.

Net income (US$/ha)'

1994/95 1995/96

C + M21 C + P2) C2) C +M C +P C

315 716 310 235 238 273

713 1153 832 230 189 153

938 1116 663 269 314 260

499 800 684 228 247 167

Weeding Methods

1. Metholachlor (1.50 kg ai/ha)


+ hand weeding3'


+ Paraquat (0.50 kg ai/ha)3)

4. Hand weeding"

" Net income is total gross income minus weeding costs.

2) C +M = Cassava intercropped with mungbean.

C + P= Cassava intercropped with peanut.

C = Cassava sole crop.

3) in 1994/95 hand weeding and application of Paraquat were done twice, while in 1995/96 this

was one three times.


234

Table 15. Recommended cultural practices for cassava production in Thailand in 19%.

Varieties: Rayong 1: high yield stability, bitter

Rayong 2: good eating quality

Rayong 3: high starch content, bitter

Rayong 60: high yield even when harvested at 8-10 months, relatively high

starch content, bitter

Rayong 90: high starch content, higher yield and longer stems than Rayong 3,

bitter

Rayong 5: high yield, relatively high starch content, bitter

Kasetsart 50: high yield, relatively high starch content, bitter

Planting time:

Land preparation:

Planting material:

Planting method:

Plant spacing:

Fertilization:

Weeding:

Harvest:

Intercropping:

May-June or Oct-Nov.

Plowing once or twice at 15-20 cm depth with tractor;

followed by once or twice disc-harrowing; ridging by oxen or tractor.

Select healthy 10-12 month old plants, cut mature stems, store

in shade (less than 30 days), cut stakes of 15-25 cm length

Planting on ridges is needed when soil is wet and contour ridges are also

very effective in reducing erosion on sloping land; flat planting when soil

moisture is low; plant vertically at 5-10 cm depth;

80-100cm between rows, 80-100 cm between plants.

100kg N, 50 P2Os, and 100 K2O/ha applied as compound fertilizers

(such as 15-15-15) supplimented with urea and KC1;

side-dressed after first weeding at 1-2 months.

On sloping land; application should be split as follows:

50 kg N, 50 P2O5 and 50 K2O/ha applied as compound fertilizer, side-

dressed after first weeding at 1-2 months; followed by 50 kg N/ha as urea

and 50 kg K2O/ha as KC1, side-dressed at 2-3 months.

2-3 times manually, at 30-45 days and 2-3 months later;

or application of Metholachlor (1.5 kg ai/ha) directly after planting,

followed by 1-2 hand weedings or spot application of Paraquat (0.5 kg/ha)

At 10-12 months, during dry season

Cassava may be intercropped with two rows of peanut or mungbean; 20

cm between rows, 10 cm between plants.

REFERENCES

Khon Kaen Field Crops Research Center (KFCRC). 1992-1995. Annual Reports for 1991-1994.

Field Crops Research Institute, Department of Agriculture, Thailand, (in Thai)

Rayong Field Crops Research Center (RFCRC). 1992-1996. Annual Reports for 199 1-1995. Field

Crops Research Institute, Department of Agriculture, Thailand, (in Thai)

Sittibusaya, C, C. Tiraporn, A. Tongglum, U. Cenpukdee, V. Vichukit, S. Jantawat

and R.H. Howeler. 1995. Recent progress in cassava agronomy research in Thailand.

In: R.H. Howeler (Ed.). Cassava Breeding, Agronomy Research and Technology

Transfer in Asia. Proc. 4th Regional Workshop, held in Trivandrum,Kerala, India.

Nov 2-6, 1993. pp. 110-123.

Tongglum, A., V. Vichukit, S. Jantawat, C. Sittibusaya, C. Tiraporn, S. Sinthuprama and

R.H. Howeler. 1992. Recent progress in cassava agronomy research in Thailand. In:

R.H. Howeler (Ed.). Cassava Breeding, Agronomy and Utilization Research in Asia. Proc.

3d Regional Workshop, held in Malang, Indonesia. Nov 22-27, 1990. pp. 197-223

235

RECENT PROGRESS IN CASSAVA AGRONOMY RESEARCH IN VIETNAM

Nguyen Huu Hy\ Pham Van Men2, Nguyen The Dang3 and Thai Phien*

ABSTRACT

In recent years the National Root and Tuber Crops Program of Vietnam, with the

cooperation and assistance of the Centro International de Agricultura Tropical (CIAT), has drawn

up a plan for strengthening the research and development capacity, with the objective of improving

cassava production in Vietnam.

In the area of cassava agronomy, the program has obtained the following results:

- Among various intercropping systems, the interplanting of cassava with peanut,

mungbean or maize were the most promising on high fertility soils, while intercropping with

peanut was promising on the poorer soils.

- Intercropping cassava with black bean or peanut and planting contour hedgerows of

Tephrosia Candida was the best way to control soil erosion. Cassava intercropped or alley

cropped with hedgerow species did not show a significant benificial effect on cassava yield at

Hung Loc Center, but the effect may be observed in the long term.

- The cassava population of 10,000-14,000 plants/ha and 12,000-16,000 plants/ha should

be recommended for the red Latosol and the grey Podzolic soils, respectively.

- Long term N, P and K trials have shown that the response of cassava to fertilizers is

very different for the various types of soils; on the more fertile Latosols the response was not

significant even in the fourth year of cropping, but on the grey Podzolic soil in the South and on

red-yellow Ferralsols in the north the response of cassava was highly significant already in the

first year, with the main response to N and K, respectively.

- Short term N, P and K trials showed a high response of cassava to K in Vinh Phu

province, as well as a higher income due to fertilizer application in Dong Nai province.

INTRODUCTION

In Vietnam, the statistical data for 1992 show that agriculture accounted for 43%

of the national gross production and 51.3% of the national income. Crop production

accounted for 76% of the total agricultural production, in which food crop production

plays an important role, occupying 98% of the total area cultivated to annual crops. Rice

production is the most important, followed by maize and cassava. The annual cassava

cultivated areas is about 280,000 ha, accounting for 25% of the food crop area; the

cassava production areas are distributed in all the different regions of the country (Figure

1).

1 Hung Loc Agric. Research Center (HARC) of IAS, Thong Nhat, Dong Nai, Vietnam.

2 Institute of Agricultural Sciences of South Vietnam (IAS), Ho Chi Minh city, Vietnam.

3 Agro-forestry College of Thai Nguyen University, Thai Nguyen, Bac Thai, Vietnam.

4 Institute for Soils and Fertilizers, Chem, Tu Liem, Hanoi, Vietnam.

236

Province* Caaaava area

I'OOO hai

1. Ha Noi 0 7

2. Ho Chi Minn 0 /

3. Hai Phong 0 4

4. Ha Giang 6 b

5. Tuyen Quang 8 1

6. Cao Bang 2.1

7. Lang Son 3 b

8. Lai Chau 8 8

9. Lao Cai S.8

10. Yen Bai 10.1

11. Bac Thai 4.8

12. Son La 13.7

13. Vinh Phu 13 2

14. Ha Bac 9 5

15. Quang Ninh 3.3

16. Ha Tay 4 3

17 Hoa Binh 14 8

18. Hai Hung 0 3

19. Thai Binh 0.0

20. Nam Ha 0 7

21. Ninh Binh 1.9

22. Thanh Hoa 16.2

23. Nghe An 14.1

24. Ha Tinh 2.3

26. Quang Binh 4 4

26. Quang Tri 3.8

27. Thua Thien-Hue 6.2

28. Quang Nam-Da N ang 17.0

29. Quang Ngai 11.3

30. Binh Dinh 12.2

31 Phu Yan 4.8

32. Khanh Hoa ; b

33. Ninh Thuan i i

34. Binh Thuan 6.8

35. Kon Tum 7.2

36. Gia Lai 9.7

37. Dae Lac 4.8

38. Lam Dong 2.6

39. Song Be

40. Tay Ninh

41 . Dong Nai

42. Long An

43. Dong Thap

44. An Giang

45. Tien Giang

46. Ben Tre

47. Vinh Long

48. Tra Vinh

49. Can Tho

50. Soc Trang

51 . Kien Giang

52. Minh Hai

Figure L Cassava planted area in the various provinces of Vietnam.

237

Ranked in third position among food crops, cassava is of special importance because

it is not only a human food but is also used as a source of feed for animals and as a raw

material for the processing industry. Cassava is also an important crop for poor farmers

in the nutrient poor soil areas, where other crops can not be planted. The soils cultivated

to cassava are generally slopy or hilly, degraded and often eroded. And these soils are

often of low pH, have low levels of organic matter, are deficient in K and may lack some

micronutrient elements (data of soil analysis by CIAT; Howeler, 1995).

Grown mainly on nutrient poor soils, farmers generally plant cassava at a population

from 10,000 to 15,000 plants/ha, dependent on the type of soil, the variety and the time

of cassava planting, as well as the tradition of the farmers. In some small areas, cassava

is usually intercropped with legume crops, such as peanut, mungbean, and cowpea, or

with contour hedgerows of leguminous trees to reduce erosion and improve soil fertility.

The importance of intercropping varies between regions; it occupies about 10% in the

north and 30% in the south of Vietnam (Pham Van Bien and Hoang Kim, 1996).

Until now, the inputs used for cassava production are still very low and the total

production costs varies between regions, ranging from US$1 16.69 to 224.83 (Figure 2).

Depending on the local conditions and the likely benifits obtained, farmers plant cassava

with or without fertilizers, the cost of fertilizer application being about 19% of the total

cost in the north and 12% in the south of Vietnam (Figure 3).

RESEARCH RESULTS

Intercropping

In Vietnam many people believe that intercropping of cassava can increase soil

fertility and reduce erosion, but some experimental results indicate that the net return is

lower than for cassava monocropping. Research by Hoang Kim and Buresova(1987) on

cassava intercropping with peanut, mungbean and winged bean showed that most of the

intercropping systems gave higher economic returns. Other intercropping trials have

been conducted on the red Latosol soil at Hung Loc Research Center in South Vietnam

for four years, using various grain legumes and maize, with the objective of controlling

weeds, preventing soil erosion, improving soil fertility and increasing income. The

results showed that on the red Latosol soil cassava intercropped with peanut, mungbean

or maize were the most promising systems. But cassava monocropping still gave higher

economic returns than any other intercropping system, while cassava planted in single

rows gave higher profits than planting in double rows (Nguyen Huu Hy et al., 1995).

Two intercropping trials were also conducted on red-yellow Ferralsols and on grey

Podzolic soils at the Agro-forestry College in Thai Nguyen of Bac Thai province and in

Thuan An of Song Be province, respectively. The results of both trials (Table 1)

indicate that on these nutrient poor soils, cassava intercropped with peanut produced by

far the highest total gross income in both locations, followed by mungbean. Cassava

intercropped with maize and soybean produced the lowest gross income.

238

Table 1. Effect of various intercropping systems on the yield of cassava and

intercrops as well as total gross income in Agro-forestry College # 3, in Bat-

Thai, north Vietnam (A), and in Thuan An, Song Be, south Vietnam (B),

in 1993.

Cropping systems1' Cassava Intercrop Gross

root yield yield income

(t/ha) (t/ha) COOOd/ha)

A. Agric. College, BacThai (Av. 4 years)"

Cassava monoculture 21.9 - 4,927

Cassava+ peanut 20.2 0.815 7,071

Cassava+ black bean 17.0 0.376 5,141

Cassava+ mungbean 21.2 0.135 4,242

Cassava + soybean 20.4 0.170 5,270

Cassava+ maize 17.5 1.257 5,320

B.Thuan An, Song Be (1 year)2'

Cassava monoculture 41.5 - 11,620

Cassava + peanut 38.1 0.70 13,132

Cassava+ cowpea 40.2 - 11,256

Cassava+ cucumber 39.5 - 11,060

Cassava+ mungbean 38.2 - 10,696

Cassava+ maize 23.8 - 7,364

11 variety:

prices :

Vinh Phu

cassava:

peanut:

blackbean:

mungbean:

soybean:

maize:

225 d/kg fresh roots

3,100 d/kg dry pods

3,500 d/kg dry grain




variety:

prices:

KM 60

cassava:

peanut:

maize:

280 d/kg fresh roots

3000 d/kg dry pods

2000 d/kg dry grain

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240

Labor 60 %

Materials 7.0 %

North Vietnam

Implements 2.0 %

Other 4.4 %

Packing 2.0 %

Traction 5.6 %

Fertilizer 19.0 %

Total cost : US$ 179.69/ha

South Vietnam

Labor 61.7 %

Implements 1 .4 %

Other 7.2 %

Packing 0.3 %

Traction 8.1 %

Materials 9.4 %

Fertilizer 1 1 .8 %

Total cost : US$ 133.09/ha

Figure 3. Relative cassava production cost shares in North and South Vietnam in

1991.

Source: Phan Thanh Binh et al. , 1996.

241

Crop Management Practices for Soil Erosion Control and Soil Fertility Maintenance

In Vietnam, about 55% of cassava is grown on flat land and 45% on slopy or

hilly land (Pham Van Bien and Hoang Kim, 1996). Because of the long crop cycle of

cassava and its slow early growth, soil loss due to erosion is a serious problem,

especially during the first three to four months after planting. Studies on crop

management practices have been conducted at some locations in Vietnam on slopes

ranging from 10 to 20%. Figure 4 shows that on 10% slope at the Agro-forestry

College in Bac Thai, cassava intercropped with black bean and with contour hedgerows

of Tephrosia candida, or planting cassava on contour ridges, reduced soil losses

significantly. In another trial on the same site, the intercropping with black bean and

Tephrosia hedgerows resulted in low levels of erosion, high cassava yield and the highest

gross income (Table 2).

A trial on intercropping cassava with legumes and leguminous tree species, with

the objective of improving soil fertility, has been conducted at Hung Loc Research Center

for four years. The results (Table 3) show that during the fourth year cassava

intercropped with Centrosema acutifolium gave the highest yield, while alley cropping

with Gliricidia sepium or Leucaena leucocephala increased cassava yields only slightly.

The beneficial effect of these treatments is expected to increase over time.

Cassava Plant Population

The most suitable cassava plant density and population depends on soil

conditions, on the variety, on the inputs used, and on the experience of the farmers.

Cassava population trials were therefore conducted on a red Latosol soil and a grey

Podzolic soil at Hung Loc Research Center and in Ho Nai 4 village of Dong Nai

province, respectively, with the objective of determining the most suitable cassava plant

density and population in the two main types of cassava soils in South Vietnam. Figure

5 shows that on the more fertile Latosol the best plant population for two cassava

varieties (KM60 and KM94) ranged from 10,000 to 14,000 plants/ha, as these

populations gave the highest yield and harvest index. On the more infertile Podzolic soil

the population range of 12,000-16,000 plants/ha gave the highest yield and profits of two

cassava varieties (Table 4). However, the starch content in the roots of these cassava

varieties varied from treatment to treatment.

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erosion in cassava planted on about 10% slope in Agro-forestry College ofBac

Thai, North Vietnam, in 1993.

244

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Figure 5. Effect ofplant population on root yield, harvest index and starch content oftwo

cassava cultivars grown in Hung Loc Research Center, in Dong Nai province

of Vietnam in 1995/96.

245

25.48bc 16.87 0.66 29.25

25.51bc 17.19 0.67 29.13

24.42c 16.04 0.65 29.40

27.92ab 17.82 0.63 28.48

29.83a 19.27 0.64 29.65

27.25abc 18.02 0.66 29.50

26.05bc 16.78 0.64 29.30

26.48bc 18.56 0.70 29.55

Table 3. Effect of intercropping and alley cropping on the yield and starch content

of cassava, KM-60, grown in Hung Loc Research Center in 1995/1996

(4th year).

Treatment" Root yield Top yield Harvest Starch

(t/ha) (t/ha) index content(%)

Cassava monoculture

C +C for forage production

C + C for mulch application

C + Tephrosia candida hedgerows

C + Cowpea intercrop

C + Canavalia ensiformis intercrop

C+Leucaena leucocephala hedgerows

C + Gliricidia sepium hedgerows

F-test *

"C= cassava

Long-term Fertility Maintenance

Cassava is a crop that is easy to plant and which can be grown on nutrient-poor

soils. But to produce high yields, to obtain high economic returns and maintain soil

fertility it is necessary to apply fertilizers or manure. Long-term NPK trials were

therefore conducted at various locations having two main types of cassava soils in both

the north and south of Vietnam. The results indicate that on the red Latosol soil at Hung

Loc Research Center in South Vietnam the response of cassava to fertilizers was not

statistically significant during the first three years of cropping. But in the fourth year

(Figure 6) there was a significant response to NPK application and in the fifth and sixth

year (Figure 7A) the response of cassava to fertilizers was very clear. The application

of 80:40:80 and 160:80:160 in kg/ha of N, P205 and K20 gave higher yields than other

treatments.

Figure 8 shows the response to annual N, P and K application during the first

six years of cropping in Hung Loc Center, as well as the relative response and the levels

of exchangeable K and available P in the soil. The latter indicate that these soils are

quite high in P and K, but that with continuous cassava cropping the P and K levels

decreased. Although cassava yields in almost all treatments increased with successive

cropping, mainly due to a change to higher yielding varieties in the 4th and subsequent

years, the relative yield of the K-check plot decreased, indicating an increasing response

to K application.

Another trial was conducted on the same red Latosol soil at Hung Loc Research

Center, but planting at the end rather than at the beginning of the rainy season. The

246

results, shown in Figure 7B, indicate that there was a significant response of cassava to

N, P and K already in the first year, and the application of 80:40:80 produced the highest

yield.

Table 4. The results ofa cassava population trial conducted on grey Podzolic soil in Ho Nai 4 village

of Thong Nhat, Dong Nai in 1995.

Variety KM 94 Variety KM 60

Plant

population Root Gross Production Net Root Gross Production Net

(plants/ha) yield income costs income yield income costs income

(t/ha) fOOOd/ha) ('000d/ha) ('000d/ha) (t/ha) (■000d/ha) ('OOOt/ha) ('OOOd/ha)

8,000 19.70 9,259 4,750 4,509 18.31 8,065 3,750 4,885

10,000 24.53 11,259 5,250 6,279 21.82 21,820 10,255 4,000

12,345 22.65 10,645 5,650 4,995 24.88 11,693 4,193 7,500

13,840 23.91 11,237 6,210 6,027 24.74 11,627 4,480 7,117

15,625 25.58 12,022 6,350 5,672 24.67 11,594 4,403 7,191

17,778 24.13 11,341 7,090 4,251 23.59 11,087 4,872 6,215

Other long-term NPK trials were conducted at four locations on light-textured

red-yellow Ferralsols and grey Podzolic soils of Vietnam. The results, shown in Figure

9, indicate that in Agro-forestry College in Bac Thai the response of cassava to fertilizers

was already very clear even in the first year, especially the response to K; in subsequent

years the response to N and K increased, while the response to P was usually significant

but did not change much over time. The application of 160 kg N, 80 P205 and 160

K20/ha gave highest yields during the sixth year of continuous cropping (Figure 10).

Similarly, results from trials conducted in Thu Duc in Ho Chi Minn City and in Ho Nai

4 of Thong Nhat in Dong Nai province (Figures 11 and 12) indicate that the response

of cassava to fertilizer application was clear already in the first year; the application of

80:40:80 and 160:80:160 again gave highest yields. Figure 12 also indicates that

increasing levels of applied N decreased, while increasing levels of K tended to increase

root starch contents. P application had little effect on root starch content.

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availabel P (Bray 2) content of the soil during seven years of continuous cropping in

Hung Loc Research Center, Dong Nai, South Vietnam.

250

Short-term NPK Requirements

In 1993 and during 1993/94 two short-term NPK trials were conducted in Tang

Hoa, Vinh Phu province, and in Xuan Thanh, Thong Nhat, Dong Nai province. Table

5 shows that in Tang Hoa there was a marked response of cassava to K application. The

application of 160 kg K20/ha gave the highest yields, while without K yields were

lowest, both at intermediate and high rates of application of N and P. Analyses of leaf

samples indicate that K concentrations in YFEL-blades were lowest in those treatments

without K application.

Table 6 shows that on the red Latosol soil at Xuan Thanh in Dong Nai province

application of 60 kg N, 60 P2O5 and 120 K20/ha, with or without application of 500 kg

lime and 40 kg MgS04/ha, produced the highest cassava yields and economic returns.

Future Direction

The following research topics are considered of highest priority in the future:

- Intensification of research on various cropping systems involving cassava.

- Development of management practices that reduce soil erosion when cassava is grown

on slopes.

- Release of new agronomic technologies to increase yields and reduce production costs.

- Establishment of a fertilizer program to improve the efficiency of fertilizer use.

- Research on more effective weed control methods.

Table 5. Effect of application of various levels of N, P and K on cassava root yield,

the nutrient concentration in YFEL blades at 6 months after planting in

Tang Hoa, Vinh Phu province in 1993.

Fertilizers Root yield Nutrient concentration%) in YFEL blades

applied (t/ha)

(kg N-P205-K20/ha) N P K

N40 P40 K0 10.2 3.87 0.31 0.83

N40 P40 K80 13.2 3.47 0.27 1.42

N40 P40 K160 14.9 3.43 0.20 1.44

N80 P80 K0 10.3 3.50 0.32 0.92

N80 P80 K80 14.5 3.72 0.30 1.52

N80 P80 K160 15.3 3.64 0.25 1.62

Source: Nguyen Huu Hy et al. , 1995a.

251

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REFERENCES

Hoang Kim and M. Buresova. 1987. The economics of winged bean on manioc as natural support

under the conditions of South Vietnam. In: Agriculture Tropica et Subtropica, Universitas

Agriculturae, Paraga.

Howeler, R.H. 1995. Results of soil analyses in Asia. In: R.H. Howeler (Ed.). Cassava Breeding,

Agronomy Research and Technology Transfer in Asia. Proc. 4th. Regional Workshop held in

Trivandrum, Kerala, India. Nov 2-6, 1993. pp. 447-464.

Nguyen Huu Hy, Tran Dai Nghia and Pham Van Bien. 1995a. Recent progress in cassava

agronomy research in Vietnam. In: R.H. Howeler (Ed.). Cassava Breeding, Agronomy

Research and Technology Transfer in Asia. Proc. 4th Regional Workshop held in Trivandrum,

Kerala, India. Nov. 2-6, 1993. pp. 237-252.

Nguyen Huu Hy, Hoang Kim and Tong Quoc An. 1995b. Results of the research on NPK

application in the South Coastal and the Southeastern regions of Vietnam. Paper presented at

seminar at Hung Loc Center, (in Vietnamese)

Nguyen Huu Hy, Nguyen Thi Sam and R.H. Howeler. 1995c. Results of the research on root and

tuber crops in Vietnam (1991-1995). In: Annual Report, (in Vietnamese)

Nguyen Van Thang. 1992. Cassava in Vietnam-an Overview. In: R.H. Howeler (Ed.). Cassava

Production, Processing and Marketing in Vietnam. Proc. of a Workshop held in Hanoi,

Vietnam. Oct 29-31, 1992. pp. 12-33.

Pham Thanh Binh, Nguyen Minn Hung, Le Cong Tru and G. Henry. 1996. Socio. -economic

aspects of cassava production, marketing and rural processing in Vietnam. In: R.H. Howeler

(Ed.). Cassava Production, Processing and Marketing in Vietnam. Proc. of a Workshop held

in Hanoi, Vietnam. Oct 29-31, 1992. pp. 113-158.

Pham Van Bien and Hoang Kim. 1990. Cassava production and research in Vietnam: Historical

review and future direction. In: R.H. Howeler (Ed.). Cassava Breeding, Agronomy and

Utilization Research in Asia. Proc. 3rd Regional Workshop held in Malang, Indonesia.

Oct 22-27, 1990. pp. 106-123.

Pham Van Bien, Hoang Kim and R.H. Howeler. 1996. Cassava cultural practices in Vietnam. In.

R.H. Howeler (Ed.). Cassava Production, Processing and Marketing in Vietnam. Proc. of a

Workshop held in Hanoi, Vietnam. Oct 29-31, 1992. pp. 58-97.

257

CASSAVA SOILS AND NUTRIENT MANAGEMENT IN SOUTH VIETNAM1

Cong Doan Sat2 and Pol Deturcld

INTRODUCTION

In South Vietnam, cassava is grown both in the highlands and in the delta, on

different soil groups, such as the yellowish red soils, grey degraded soils, alluvial soils

and acid sulfate soils. These soils are located mostly in the Central Highlands, the

Coastal Region and the Eastern Region of South Vietnam, where perrenial crops such as

coffee, tea and rubber are also grown. Cassava is often grown on unfertile soils. As a

result, the soil becomes poorer and poorer leading to a decline in soil productivity.

Sloping lands under cassava cultivation are quickly eroded after deforestation.

Besides, the soil organic matter content also decreases due to forest burning and leveling

and as a result of the direct impact of sunshine and rain drops. The soil will be

chemically and physically degraded. Similarly, the soil microbial activity also declines.

To obtain a high and sustainable yield of cassava, it is necessary to use some

investment for cassava cultivation. But most cassava farmers are too poor to invest in

fertilizers, so the soils quickly lose their productivity. Therefore, better nutrient

management is required to maintain sustainable cropping systems, by reducing erosion

and preventing a decline in soil fertility.

CHARACTERISTICS OF CASSAVA SOILS IN SOUTH VIETNAM

In South Vietnam, the soils used for cassava cultivation include the three major

groups: Acrisols, Arenosols and Ferralsols (Pham Quang Khanh, 1997). They have the

following characteristics (Table 1):

Topography, soil depth

Most of the land used for cassava cultivation has an undulating topography and

the slope is usually less than 25%, which is convenient for transportation and

mechanization. The soil depth is generally greater than 100 cm, which enhances good

root development.

1 Paper presented at the Workshop on Cassava in Vietnam, Ho Chi Minn city, 5-7 March,

1997.

2 Soils and Fertilizers Department, Institute of Agricultural Sciences of South Vietnam (IAS),

121 Nguyen Binh Kiem Street, Ho Chi Minh city, Vietnam.

3 Vietnam-Belgium Project on Sustainable Agric. Developm. in Uplands of South Vietnam,

IAS, 121 Nguyen Binh Kiem Street, Ho Chi Minh city, Vietnam.

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Soil physical properties

Soil texture varies from light (sand, sandy loam) to moderately heavy (clay

loam, clay); the latter are found in the yellowish red soils derived from basalt or schist.

Soils with light texture are well-drained and very suitable for cassava root formation; the

light texture also facilitates the harvest. However, heavy soils of South Vietnam have

good aggregation due to a high Fe content. The soils are porous and well-drained. But

most cassava soils have been poorly managed, without much surface cover. This has

resulted in the destruction of soil structure, leading to compaction which makes

harvesting more difficult.

Soil chemical properties

Cassava is a relatively undemanding crop. Root yields of about 10 t/ha can be

obtained on soils which can not be utilized for growing other crops. Due to this

characteristic, farmers often exploit as much as possible the nutrient resources in the soil

to produce their products.

The degradation of cassava soils can be seen through their chemical and physical

properties:

-low pH: 4.5-5.0

-high level of exchangeable Al, and high Al saturation

-low base saturation; low levels of exchangable Ca, Mg and K

-low level of available P and high P fixing capacity

-low CEC

-low organic matter content

-low microbial activity

-low soil permeability

To study the sustainability of different cropping systems in the Eastern Region

of South Vietnam, areas were identified in Thay Ninh, Song Be and Dong Nai provinces

where forest, rubber, sugarcane, cashew and cassava had been grown continuously for

many years, in close proximity to each other, in similar landscapes, on similar grey

podzolic soils (Haplic Acrisols) with similar profile characteristics. For each cropping

system at least seven soil pits were dug and samples were taken in the different profile

horizons. Both the soil physical and chemical characteristics were determined and the

data were averaged over the seven or more profiles. Figures 1 through 5 and Table 2

show the results of these analyses. Compared with other cropping systems, cassava soils

had the lowest clay content (Figure 1) and lowest aggregate stability (Figure 2), the

second lowest infiltration rate (Figure 4) and third highest bulk density (Figure 3).

Cassava soils also had the lowest level of volumetric water content at different matric

pressure heads, ranging from saturation to wilting point (Figure 5). This indicates that

260

during cassava cultivation the soil had differentially lost part of its clay, resulting in a

lighter soil texture and lower aggregate stability. Compared with natural forest, cassava

soils were also more compacted, resulting in a significantly higher bulk density and lower

water infiltration rate. Soils under rubber were even more compacted than those under

cassava, and they had a similarly low clay content and aggregate stability.

Table 2 shows that cassava soils generally had significantly lower levels of cation

exchange capacity (CEC), organic carbon and total N, and lower levels of exchangeable

K and Mg than rubber and sugarcane; they tended to have similar chemical characteristics

as soils under cashew, except for P, which was considerably higher under cassava than

cashew. Soils under rubber and sugarcane tended to have higher levels of fertility due

to the higher rates of fertilization used on those crops. These data indicate that soils used

continuously for cassava cultivation, generally without adequate levels of fertilization,

will become degraded due to soil (especially clay) loss by erosion, as well as by

compaction and nutrient depletion. The cultivation practices currently used for cassava

in South Vietnam can not maintain the sustainability of the system.

Table 2. Chemical properties of various horizons of Haplic Acrisols that have been

under different land use in southeastern Vietnam.

Forest Rubber Sugarcanes Cashew Cassava CV(%)

Organic C (%) 1.032 a 0.839 ab 0.796 ab 0.579 ab 0.496 b 44.7

Total N (%) 0.058 a 0.054 ab 0.040 abc 0.032 bc 0.022 c 36.7

Available P (Bray II)(ppm)

- 1st horizon 5.21 b 20.90 a 20.68 a 4.85 b 15.33 ab 37.5

- 2nd horizon 2.48 b 7.03 a 7.92 a 3.19 b 5.31 ab 32.6

- 3rd horizon 1.57 b 2.83 ab 3.82 a 1.08 ab 3.82 a 44.6

CEC (me/lOOg) 3.43 a 2.94 a 3.24 a 2.39 ab 1.53 b 27.1

Exch. K (me/lOOg)

- 1st horizon 0.132 a 0.127 a 0.051 b 0.070 ab 0.060 b 66.3

- 2nd horizon 0.073 a 0.046 ab 0.022 b 0.031 ab 0.021 b 75.1

Exch. Mg (me/lOOg) 0.145 a 0.157 a 0.055 ab 0.046 ab 0.036 b 89.1

Values are average of 6^10 profiles per cropping system. Within rows data followed by the same letter are

not significantly different at 5% level by Tukey's Studentized Range Test.

261

30 -

* 25

c

acco

>-•

5 20

15

Forest Cashew Rubber Cassava

Figure 1. Clay content of Haplic Acrisols under different cropping systems. Values are

the average of 7 profiles per cropping system. Bars with common letter

are not significantly different at 5% by Duncan's Multiple Range Test.

3.0-

o

2.0-

M 1.0

bbe

-

cd

Forest Sugarcane Cashew Rubber Cassava

Figure 2. Aggregate stability of Haplic Acrisols under different cropping systems. Values

are the average of at least 7 profiles per cropping system and 3 horizons per

profile. Bars with common letter are not significantly different at 5% by

Tukey 's Studentized Range Test.

Note: Aggregate stability class: 1= highly unstable, 2 — unstable, 3= relatively stable,

4=stable

262

.60

E

cLI■a

3

1.50

1.40

1.30 -

ab

cd

Forest Sugarcane Cassava Cashew Rubber

Figure 3. Bulk density of Haplic Acrisols under different cropping systems. Values are

average of at least 7 profiles per cropping system and 3 replicates per

horizon. Bars with common letter are not significantly different at 5%

by Tukey 's Studentized Range Test.

r3

C

C

40 r

30-

20 -

E 10-

Forest Sugarcane Cashew Cassava Rubber

Figure 4. Infiltraton rate ofHaplic Acrisols under different cropping systems. Values are average

of at least 7 profiles per cropping system and 3 replicates per profile. Bars with

common letter are not significantly different at 5% by Tukey 's Studentized Range Test.

263

50 r

40

* 30

20 -

10-

0

a

b ^

Forest Sx Rubber Sugarcane gg Cashew jfl Cassava

lb b

:•:•:•: 1.".*.••

- ;Xva

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•yy.' .•-;.:f--:.:.:

:::::::b b a

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<m l

1 fe-:! IP 1.*■"••" . . .•.■.•"■ ••.•"■"*_

OkPa 10 kPa 100 kPa

Matrix pressure head

1500 kPa

Figure 5, Water retention of the A horizon ofHaplic Acrisols under different cropping systems.

Values are average of at least 7 profiles per cropping system and 3 samples per

horizon. For the same matrix pressure head, bars with common letter are not

significantly different at 5% by Tukey.s Studentized Range Test.

NUTRIENT MANAGEMENT FOR CASSAVA SOILS

The cassava crop extracts a relatively large amount of nutrients from the soil

(Table 3). Howeler (1991) showed that cassava removed less N and P in the harvested

product (roots) per unit of dry matter produced as compared to other crops; K removal

was found to be similar to that of other crops. Like any other crop, continuous

cultivation of cassava will deplete the soil's nutrient supply unless fertilizers are added.

Results of experiments conducted from 1989 to 1995 show that mineral fertilizers

greatly increased yields when applied at the rate of 80-160 kg N, 40 kg of P2O5 and 80-

160 kg of K2O/ha. Intercropping with peanut, mungbean or maize gave high economic

efficiency. Highest yields were obtained when cassava was intercropped with Canavalia

or when contour hedgerows of Tephrosia candida were planted (Nguyen Huu Hy et al.,

1996).

264

Table 3. Total nutrient uptake by cassava for various levels of root yield as reported

in the literature.

Plant

part

Fresh root

yield

(t/ha)

N P K Ca Authors

{Kginaj

Total 15 60 17 92 - Bui Q. Toan, 1990

Total 20

-stems + leaves

-roots

252 41 124

82

93

79

14

Nguyen Tuan

Hao, 1994238 32

14 9 42

Total 25 100 31 167 86 Le M. Du, 1995

Total 30

-stems + leaves

-roots

164 31

21

10

200 80 Asher, Edwards and

Howeler, 1980126 124 71

38 76 9

The project on the "Development of Sustainable Agriculture for the Uplands of

South Vietnam", conducted in collaboration with the Catholic Univ. of Leuven

(Belgium), showed that root yields and starch content were highest with the application

of 120-120-180 kg/ha of N-P205-K20 (Table 4). Mulching with straw improved the

yield (in one site only), but yields decreased when intercropped with red beans or mung

beans, or when cover-cropped with Calopogonium (Tables 5, 6, and 7). This may be

due to the competition for nutrients or water among crops. Depth of plowing did not

result in a significant difference in yield (Tables 6 and 7).

Table 4. Average effect of NPK-fertilizers on the yields of fresh cassava roots grown

on two Haplic Acrisols in Tay Ninh and Dong Nai provinces of South

Vietnam in 1994/95 and 1995/96.

Fertilizers applied

(kg N-P2O5-K20/ha)

Tay Ninh

root yield

(t/ha)

Dong Nai

Root yield

(t/ha)

Starch content

(%)

0-0-0

30-30-45

60-60-90

120-120-180

12.31 c 15.04 c 22.54 b

18.75 b 22.14 b 22.51 b

19.49 b 23.44 b 22.63 b

26.35 a 28.00 a 23.73 a

265

Experimental results show that the response of cassava to fertilizers varies from

place to place. There is still not enough knowledge to recommend a suitable formula for

each soil group. Increasing the dose of mineral fertilizers did not always increase crop

yields. As an example, in Thong Nhat district, Dong Nai province, when fertilizer

applications were doubled from 30-30-45 to 60-60-90, yields did not significantly

improve. However, in the same experiment, application of cassava peel compost plus

20 kg/ha N and 60 kg/ha K^O produced as high a yield as with application of 120-120-

180 kg N-P2O5-K20/ha. Therefore, organic materials can play an important role as a soil

conditioner to maintain adequate soil moisture and a high porosity for root development,

or as an additional source of major and minor nutrients.

Table 5. Average effect of mulching and inorganic fertilizer application on the fresh

root yield of cassava grown on a Haplic Acrisol in Traco village, Thong

Nhat district in Dong Nai province of South Vietnam in 1994/95 and

1995/96.

Treatment11

M0


M, Average

F0

F,

F:

F3

Average

17.84 d

21.39 c

22.04 c

24.32 ab

21.40

18.68 d 18.26

22.23 bc 21.81

22.88 bc 22.46

25.16 a 24.74

22.23

F0: 0-0-0 kg N-P205-K2O/ha

F,: 30-30-45 kg N-P205-K20/ha

F2: 60-60-90 kg N-P205-K20/ha

F3: 120-120-180 kg N-P205-K20/ha

M0: without mulch

M,: with mulch (3 t/ha of rice straw)

266

Table 6. Average effect of different management practices on the fresh root yield of

cassava grown on a Haplic Acrisol in Tan Phu village, Hoa Thanh district

in Tay Ninh province of South Vietnam in 1995/96.

Treatment Root yield (t/ha)

Intercropping system

cassava monocropping 23.43 a

cassava + straw mulching 20.96 ab

cassava + peanut intercrop 19.17 b

cassava+ cover crop (Calopogonium) 13.35 c

Land preparation

normal plowing 19.88 a

deep plowing 19.57 a

Table 7. Average effect of different management practices on the fresh root yield of

cassava grown on a Haplic Acrisol in Traco village, Thong Nhat district in

Dong Nai province of South Vietnam in 1994/95 and 1995/96.

Treatment Root yield (t/ha)

23.16 a

17.90 b

20.63 b

22.32 a

20.74 b

22.22 a

22.05 a

21.03 a

Intercropping

cassava monocropping

cassava-beans (red bean or mungbean)

Mulching

without mulch

with mulch of rice straw (3 t/ha)

Dolomite

without lime

with lime (1 t/ha)

Plowing

normal (to 20 cm depth)

deep (to 30 cm depth)

In order to maintain a sustainable level of production of cassava in South

Vietnam, it is necessary to improve the nutrient management. The problems that need

to be studied are:

-the best areas for cassava production

267

-intercropping and rotational cropping for protection against soil erosion and for

maintenance of soil fertility

-suitable combinations of organic and inorganic fertilizers, particularly by-products of

cassava processing (stem, peel, fermented products, etc..) to further enhance cassava

productivity in the future

-develop a model for improved nutrient management for typical cassava growing regions

REFERENCES

Asher, C.J., D.G. Edwards and R.H. Howeler. 1980. Nutrional Disorders of Cassava. Dept. of

Agriculture, Univ. of Queensland, St. Lucia, Qld., Australia. 48 p.

Howeler, R.H. 1991. Long-term effect of cassava cultivation on soil productivity.

Field Crops Research 26: 1-8.

Nguyen Huu Hy, Tong Quoc An and R.H. Howeler. 1996. Results of cassava agronomy

experiments in Vietnam from 1989-1995. In: Hang Kim and Nguyen Dang Mai (Eds.).

Progress in Cassava Cultivation in Vietnam. Proc. Vietnam Cassava Workshop held in Ho Chi

Minn city. March 5-7, 1996. pp. 38-43. (in Vietnamese)

Pham Quang Khanh. 1997. The potential of upland in the south of Vietnam. Agric. Publications.

In: Workshop on Nutrient and Water Management for Crops in Uplands of Southern Vietnam,

held in Ho Chi Minn city. Jan 16-17, 1997. pp. 20-29. (in Vietnamese)

268

NUTRIENT MANAGEMENT FOR CASSAVA-BASED CROPPING SYSTEMS

IN NORTHERN VIETNAM

Thai Phien1 and Nguyen Cong Vinh1

ABSTRACT

Five soil types on which cassava is being planted were investigated. Almost all these

soils are degraded in terms of soil properties, especially with respect to soil fertility. Cassava is

traditionally planted without fertilizer application and soil conservation measures, resulting in a

negative nutrient balance.

In experiments on the application of mineral fertilizers, cassava yields increased by 20-

1 1 2 % compared to the control treatment. The combination of organic manures, mineral fertilizers

and contour hedgerows to reduce erosion, increased cassava and intercropped peanut yields on

average 43-46% compared to the application of organic fertilizers only. The nutrient balance in

these areas was positive, with high income and low soil erosion.

INTRODUCTION

Cassava is an annual crop, which is popularly cultivated on sloping lands in the

northern mountainous provinces, as well as in other parts of Vietnam. Traditionally,

farmers in these regions have adopted a no-input or low-input method of cultivating

cassava.

Soil erosion and a decline in soil nutrient content, resulting in land degradation,

have been evident from many research results, and farmers are well aware of this. As

such, some soil conservationists and policy makers have recommended to replace cassava

with other crops, but in fact, thousands of hectares of cassava continue to be cultivated

every year on steep sloping lands with little or no input. Annually, cassava removes

large amount of nutrients from the soils, while under present crop management systems

the nutrient return to the soil is very small.

PROPERTIES OF SOME CASSAVA SOILS

In Vietnam cassava is planted on all soil types, but mainly on sloping lands. The

main characteristics of some of these soils are presented in Table 1. This shows that the

soil physical properties are different for soil types derived from different parent

materials. We can see that the clay fraction in the soil texture varied from 10 to 62%,

and the coarse sandy fraction from 4 to 60%. Basaltic soils have the highest content of

clay, followed by those derived from shale. The sandy and old alluvial soils have a

coarse texture. Soil bulk densities varied from 1 .08 g/cm3 in basaltic soil to 1 .50 g/cm3

in old alluvial soil. The rate of infiltration is very low in soils with high bulk density.

Run-off and erosion on these soils further lead to soil degradation.

Field capacity also varies between soil types, being 15.0% on old alluvial soil,

29.3% on soil derived on shale, and 43.8% on basaltic soil.


269

Comparing the physical properties of soils under forest with those planted to

perennial crops, indicate that soils that have been cultivated with cassava for a long time

have become degraded. For example, under secondary forest the bulk density of basaltic

soils was found to be 0.78 to 0.90 g/cm3, and the clay content 65-71 %, while the field

capacity was about 48-49% . On soil derived from shale, the bulk density was 1.15-1 .25,

the clay content 38-41% and the field capacity 30-32%.

Table 1. Characteristics of some cassava soils in Vietnam.

Soil type

Parameters

Old Shale Liparit Sandstone Basalt

alluvial derived derived derived derived

soil soil soil soil soil

12.0 34.8 26.8 10.0 62.0

60.0 17.8 34.5 62.0 3.5

1.50 1.45 1.63 1.60 1.08

15.0 29.3 19.9 16.0 43.8

5.0 15.4 8.0 5.2 23.9

10.0 13.9 11.9 10.8 19.9

3.7 3.5 4.5 3.9 3.8

1.10 2.20 0.56 1.18 2.57

0.08 0.09 0.05 0.09 0.14

0.02 0.09 0.01 0.01 0.10

0.04 0.12 0.03 0.10 -

6.3 18.3 14.5 - 36.5

0.20 0.60 0.24 0.98 0.18

0.15 0.45 0.17 0.77 0.06

4.50 8.50 14.70 4.30 18.0

Physical properties

-Clay (< 0.002mm)

-Coarse sand (2-0.2mm)

-Buld density (g/cm3)

-Field capacity (%)

-Wilting point (%)

-Effective moisture (%)

Chemical properties

■pHKCi

-C(%)

-Total N(%)

-Total P (%)

-Total K (%)

-Avail. P (mg/kg)

-Ca (me/lOOg)

-Mg (me/lOOg)

-CEC (me/lOOg)

Source: Thai Phien et al. , 1995.

Results of chemical analysis shown in Table 1 indicate that almost all cassava

soils have low pH (in KG) of 3.5-4.5 depending on the soil's parent material and cassava

cultivation practices. The soil pH is below the threshold of that suitable for cassava

growing. The soil organic matter and nutrient contents are also very low, with organic

C of 1.10-2.57%, total N 0.08-0.14%, total P 0.02-0.10%, and total K 0.04-0.12%.

Especially the available nutrient contents are low or very low and can not meet the

requirement for normal cassava growth. In terms of suitability for cassava production

with respect to nutrient content these soils can be arranged as follows: Soils derived

from basaltic rock > Soils derived from shale > Soils derived from liparit rock > Soils

270

derived from sand stone > Old alluvial soils.

This research indicate that almost all cassava cultivated soils on sloping lands are

poor to very poor in terms of nutrient content and availability. Therefore, for profitable

and sustainable cassava cultivation on these soils, reasonable inputs are needed, together

with measures to minimize soil erosion.

SOIL CHANGES UNDER CASSAVA CULTIVATION

1. Soil Degradation as a Result of Cassava Cultivation

The amount of soil eroded by rainfall in sloping areas depends on many factors,

but among these the percent crop cover in the rainy season is very important. Table 2

presents data of soil erosion as affected by crop cover. The secondary forest had a

vegetation cover of 80-90%, which resulted in the lowest amount of soil erosion. The

highest amount of soil erosion occurred in the soil under cassava.

Soil and nutrient losses by erosion are presented in Table 3. Under bush fallow,

the amount of soil and nutrient loss was the lowest in comparison with that under tea and

cassava. Contour cultivation in tea resulted in soil erosion washing away a depth of top

soil of about 2.6 mm/year and a nutrient loss of about 23 kg N, 7 P and 6 K/ha, while

the cultivation of cassava resulted in soil and nutrient losses that were 4-10 times higher

compared to tea cultivation and bush fallow.

So, it is clear that cassava monocropping on sloping lands may cause serious soil

degradation by soil erosion. It is therefore necessary to use reasonable fertilizer inputs

and erosion control measures.

The changes in soil organic matter content under cassava monocropping are

presented in Table 4. After continuous cassava monocropping the soil organic matter

content decreased due to soil erosion and organic matter decomposition. After six years

the soil organic matter content decreased to about half, and after ten years to only one

third of that present in the first year.

Data in Table 5 show that after 1-2 years of cassava cultivation the soil nutrient

content decreased if no fertilizers were applied and no erosion control measures were

used. The pH decreased 0.1-0.4 units in comparison with the same soil under forest.

Organic matter was about 59-72% compared to the soil under forest. The contents of all

nutrients also decreased after cassava cultivation.

2. Improved Management of Soil Nutrients in Cassava-based Cropping Systems

To minimize soil degradation resulting from cassava cultivation, soil conservation

measures should be applied. Some research results on the effects of fertilizer application

to conserve soil fertility and increase crop yields are presented and discussed.

Effect of application of mineral fertilizers on cassava yield

The experiments were conducted for three years on soil derived from shale.

271

Figure 1 shows that during three years of continuous cassava cultivation with no

fertilization, the yield of cassava decreased from 12.3 to 8.6 t/ha; thus, the productivity

of soil decreased to about 70% of that in the first year.

Table 2. Vegetation cover and amount of soil erosion under different crops in soil

derived on shale in Thai Nguyen province.

Vegetation/crop Crop cover (%) Soil erosion (t/ha)

Secondary forest 80-90 12.4

Maize 30-50 14.7

Upland rice 10-15 95.1

Cassava 10-15 98.6

Source: Nguyen Tu Siem and Thai Phien, 1993.

Table 3. Soil erosion and nutrient losses in eroded soil due to the cultivation of

cassava and tea in comparison with bush fallow in Than Hoa district of Vinh

Phu province.

Crops Depth of

soil loss

(mm/year)

Dry weight

soil loss

(t/ha/year)

Nutrient loss (kg/ha)

N P K

Cassava 12.3

2.6

1.0

145

33

145

23

10

48 26

7 6

2 3

Tea

Bush fallow 12

Source: Thai Phien and Nguyen Tu Siem, 1993.

272

Table 4. Change in organic matter (OM) content and composition due to continuous

cassava cultivation for various years at Phu Quy in 1994.

Soil Total OM

(%)

Humic acid

(%)

Fulvic acid

Humic/Fulvic

acid

ratio

Cassava 1 year 1.72 0.48 0.64 0.75

Cassava 6 years 0.80 0.21 0.33 0.64

Cassava 10 years 0.55 0.09 0.36 0.25

Source: Nguyen Tu Stem and Thai Phien, 1993.

Table 5. Chemical characteristics of basaltic rock derived soil under forest and

cassava cultivation at Phu Quy in 1994.

Soil depth

(cm)

Total (%)

Exchangeable

(me/ 100 g soil)

pHKa OM N P Ca Mg

Forest 0-10

20-40

40-60

4.2

4.1

4.4

5.80

3.30

3.01

0.26

0.11

0.10

0.11

0.04

0.04

2.00

1.18

1.60

0.80

0.40

0.76

Cassava

(1 year)

0-20

20-40

40-60

3.8

4.1

4.3

4.18

2.19

1.08

0.08

0.11

0.10

0.05

0.09

0.05

1.46

1.40

1.20

1.20

0.40

1.60

Cassava 0-20

20-40

3.8

3.8

3.40

2.08

0.14

0.06

0.10

0.09

0.12

0.04

0.04

0.04(2 years)

Source: Nguyen Tu Siem and Thai Phien, 1993.

273

oo

>

(/l

U

25-

20 - O

2 15

10

- - - - -°

N-P205-K20(kg/ha)

D = 0-0-0

X = 30-30-60

O = 60-60-120

1992

~l—

1993 1994

Figure 1. Effect offertilizer application on cassava yield during three years ofcontinuous

cropping on a soil derivedfrom shale in north Vietnam.

Application of NPK fertilizers increased the yield 71-1 12% in comparison with

the control. The effects of N, P and K are presented in Table 6. Application ef 30 and

60 kg N/ha increased cassava yields from 16.9 to 17.1 and 17.7 t/ha, respectively.

Application of 30 and 60 kg P2O5/ha increased cassava yields from 15.6 to 17.1 and 19.6

t/ha, respectively, 10-24% higher than the control. Application of 60 and 120 kg I^O/ha

increased cassava yields 31 and 41%, respectively, compared to the control. The

response of cassava to nutrient application in this soil can be ranked as K> P> N.

274

Table 6. Effect of annual application of N, P and K fertilizers on cassava yields.

Data are average values for three years.

Fertilizer Cassava fresh root yield Relative to

applied Treatments" (t/ha) control (%)

NPK NoPoKo 10.0 100

N,P,K, 17.1 171

N2P2K2 21.2 212

N N0P,K, 16.9 169

N,P,K, 17.1 171

N2P,K, 17.7 177

P N,P0K, 15.6 156

N,P,K, 17.1 171

N,P2K, 19.6 196

K N.P.Ko 13.1 131

N.P.K, 17.1 171

N.P.K, 19.5 195

" No=0 Po=0 Ko=0

N, = 30 kg N/ha P, = 30 kg P205/ha K, = 60 kg K20/ha

N2=60 kg N/ha P2 = 60 kg P20,/ha K2= 120 kg K20/ha

Effect of farm-yard manure, inorganic fertilizers and lime in a cassava-grain legume

intercropping system

Soil fertility improvement can also be achieved by intercropping cassava with

grain legumes in addition to fertilization. Table 7 shows that application of NPK

fertilizers combined with lime (T2, T4) increased the yield of crops, and that these yields

were higher than in the treatment with only farm yard manure (FYM). The combination

of NPK and FYM (T3, T5) produced higher yields than that of NPK and lime. This

indicates that in these hilly soils application of FYM was more effective than that of lime.

The combination of NPK with lime and FYM resulted in the highest yield. It shows that

the high level of NPK together with FYM and lime promoted the growth and yield of

crops. Cassava-legume intercropping systems can achieve yields of 1 1-19 t/ha of cassava

and 78-160 kg/ha of black bean or 550-800 kg/ha of peanut; they tend to be more

economical than monocropping of cassava.

275

Table 7. Effect of three years of annual fertilizer application on crop yields in a

cassava-grain legume intercropping system at Hoa Son in 1995.

Cassava

yield (t/ha)

Intercrop yields (kg/ha)

Black bean Peanut

Treatment1 Mean (1992-1994) (1992) (1993-1994)

1. FYM 11.5 78 546

2. low NPK+ lime 14.4 96 730

3. low NPK +FYM 16.8 129 836

4. high NPK + lime 14.8 104 731

5. high NPK +FYM 16.5 143 788

6. high NPK + lime+FYM 18.8 162 870

" FYM = 3 t pig manure/ha.

low NPK = 25 kg N, 50 P205, 50 K20/ha.

high NPK = 50 kg N, 100 P205, 100 K20/ha.

Source: Thai Phien, Nguyen Tu Siem and Nguyen Cong Vinh, 1995.

Soil nutrient balance as affected by fertilization

Every year a considerable amount of nutrients are removed by run-off and soil

erosion, as well as by crop removal (Table 8). In the case of monocropping of cassava,

the annual amount of nutrients removed by cassava was 62-153 kg N, 83-181 kg P205

and 67-147 kg K20/ha. Soil fertility will decline unless nutrients are returned to the soil

in the form of fertilizers or manures, or the crop is combined with leguminous crops like

black bean, peanut etc. between cassava rows, and the residues of these intercrops are

returned to the soil. Even with fertilization of 30-60 kg N, 30-60 P205 and 60-120

K2O/ha, the nutrient imbalance that occured varied from 62-120 kg N, 25-59 kg P and

up to 72 kg K/ha (Table 8). On the other hand, nutrients can be returned by

intercropping and mulching with crop residues. Crop residues can provide organic

matter and nutrients to the soil (Table 9) and improve the soil's physical properties. The

nutrient loss in the crop harvest of cassava and beans in a cassava-bean intercropping

system was found to be 99-153 kg N, 25-49 P, 31-40 K, 36-58 Ca and 11-19 Mg/ha.

Valuable nutrient resources would be taken out of the soil if no crop residues were

returned to the soil. The return of crop residues, especially intercropped leguminous

residues, can return to the soil about 49-80 kg N, 15-25 P, 10-15 K, 17-28 Ca, and 5-9

Mg/ha. Those are equal to about 110-180 kg urea, 300-500 kg fused magnesium

phosphate and 20-30 kg KCl/ha.

The effect of hedgerow farming and intercropping on soil fertility

In Vietnam, cassava is mostly planted on steep lands without or with very low

276

inputs, and without soil erosion control measures. One effective way to minimize soil

erosion is the planting of hedgerows of certain plant species along contour lines.

The effect of crop management on soil erosion is presented in Table 10.

Intercropping with grain legumes and contour hedgerows in combination with fertilizer

application reduced soil erosion. On bare land soil loss and run-off were highest. Run

off under monocropped cassava (T2) was reduced by 13% compared to bare land. In

cassava intercropped with beans (T3), run-off was only 84% of that of bare land (T3),

while intercropped black bean/peanut and contour hedgerows further reduced run-off and

erosion.

Fertilizer application also had a marked effect on soil erosion: in the treatments

of hedgerow farming with high inputs of fertilizers, soil loss was only 2.8-3.7 t/ha, while

with the low input treatment soil loss was 4.8 t/ha.

A large amount of nutrients can be washed out in the eroded soil. It depends on

the cultivation method and fertilizer application. These are presented in Table 11. In

an experiment conducted on an exhausted soil derived from Liparit in Tarn Dao, Phu Tho

province, 7.8 kg N, 3.9 kg P and 7.2 kg K/ha were washed out as part of the eroded soil

from bare land. In monocropped cassava (T2) nutrients are not only lost by soil erosion,

but also by removal of the crop products and residues. By intercropping cassava with

peanut and planting contour hedgerows, some nutrients are returned by mulching with

crop residues (T3, T4, T5, T6). Nutrient losses were lower in treatments with high

inputs than in those with low inputs. With high inputs and intercropping, more nutrients

were returned than lost. When peanut/black bean were intercropped with cassava, the

positive nutrient balance varied from 47 to 63 kg N, 0.3 to 2.0 kg P and 19 to 27 kg

K/ha/year.

Table 8. Effect of fertilization on the nutrient balance in soil after cassava

monocropping at Hoa Son, 1995.

kg N/ha kg P205/ha kg K2O/ha

TreatmentFD

R" F-R F R F-R F R F-R

Tl 0 62 -62 0 36 36 0 56 56

T2 30 108 -78 0 54 54 42 85 43

T3 30 76 -46 13 49 36 0 72 72

T4 30 135 -105 13 38 25 84 73 11

T5 30 125 -95 13 63 50 42 97 55

T6 0 120 -120 13 61 48 42 94 52

T7 60 134 -74 13 72 59 42 111 69

T8 30 138 -108 26 69 43 42 108 66

T9 60 153 -93 26 79 53 84 122 63

" p =F = applied in fertilizers; R = removed in crop

277

Table 9. Biomass and nutrients removed or returned (kg/ha) to the soil in a

cassava-bean intercropping system at Hoa Son, 1995.

Biomass

Treatments returned N P K Ca Mg

Tl L" 99 24.9 31.2 35.7 11.4

R" 3910 49 14.7 10.1 17.1 5.4

T2 L 118 36.9 36.3 45.7 14.5

R 4050 60 18.5 12.1 20.7 6.6

T3 L 121 39.3 39.3 45.0 15.7

R 4220 64 19.7 13.1 22.9 7.2

T4 L 135 43.1 41.3 50.7 16.9

R 4450 76 22.2 14.1 25.7 8.4

T5 L 136 43.1 45.4 54.3 17.5

R 4910 79 24.6 15.2 27.1 9.0

T6 L 153 49.2 46.4 57.8 19.3

R 507 80 24.8 15.2 27.9 9.0

" L = Lost in crop harvest; R = Returned in crop residues

Source: Thai Phien, Nguyen Tu Siem and Nguyen Cong Vinh, 1995.

Table 10. Soil loss and run-off from degraded soil derived from Li pari t

(slope: 9-12%) at Tarn Dao, Vinh Phu in 1994.

Run-off Dry sofl loss

Treatment Cultivation measures

Tl Bare land (control)

T2 Cassava monocrop

T3 Cassava + black bean or peanut with low input

T4 Cassava + bean or peanut + hedgerow + low input

T5 Cassava + bean or peanut + hedgerow + high input

T6 Cassava + bean or peanut + mixed hedgerow +

high input

m3/ha/year t/ha/year

14,539 6.9

12,678 6.9

12,233 6.1

12,031 4.8

11,473 2.8

10,674 3.7

Source: Huynh Due Nhan et al. , 1995.

278

Table 11. Nutrient loss in eroded soil and return in crop residues (kg/ha/year) at

Tarn Dao, Vinh Phu in 1994.

N P K

Treatment" L: R2> D L R D L R D

Tl 7.8 0 -7.8 3.9 0 -3.9 7.2 0 -7.2

T2 7.6 0 -7.6 5.7 0 -5.7 6.2 0 -6.2

T3 6.7 66.2 + 59.5 5.6 5.9 + 0.3 7.3 30.4 +23.1

T4 8.1 55.3 + 47.2 4.8 5.3 + 0.5 7.6 26.6 + 19.0

T5 4.5 67.2 +62.7 4.4 6.3 + 1.9 5.9 33.4 + 27.5

T6 6.7 60.3 +53.6 4.3 6.3 + 2.0 6.7 31.8 +25.1

" Treatments as in Table 10

21 L = Loss; R = return with crop residues, D = R-L.

Source: Huynh Due Nhan et al., 1995.

The effect of fertilization and biological technology on crop yield

The effect of fertilization and intercropping with grain legumes on crop yields

is shown in Table 12. Fertilization and contour hedgerows increased the total gross

income obtained in a cassava-peanut intercropping system. Monocropping of cassava

produced a yield of 10.8 t/ha, while the intercropping system produced 7-9 t/ha of

cassava and 450-500 kg/ha of peanut per year, resulting in a gross income of 5.5-6.6

million dong/ha, compared with 4.9 million dong/ha for monocropping.

Table 12. Effect of soil and crop management practices on the yields of cassava and

intercrops, as well as on total gross income in Tan Dao, Vinh Phu

in 1994.

Yield of cassava Yield of peanut Gross income2)

Treatments" (t/ha) (kg/ha) C000d/ha)

T2 10.8 0 4860

T3 9.1 498 6585

T4 7.6 450 5670

T5 7.9 466 5885

T6 6.9 479 5500

" Treatments as in Table 10

2) Prices: cassava d 450 /kg fresh roots,

peanut 5000 /kg dry pods.

Source: Huynh Due Nhan et al. , 1995.

279

CONCLUSIONS

1 . In nearly all soils used for cassava cultivation adequate soil erosion control measures

have not been used; as a result, they have become degraded in terms of soil physical

properties and nutrient contents.

2. Application of mineral fertilizers to cassava markedly increased cassava root yields,

the increase ranging from 20 to 112% compared with the control treatment without

fertilization.

3. The combined application of organic and mineral fertilizers increased cassava yields

43-46% compared to the application of organic manures alone. Highest cassava yields

were obtained when combining organic and mineral fertilizers with lime.

4. Intercropping grain legumes (bean, peanut) between cassava rows reduced tbe amount

of soil loss by 22-59% compared to cassava monocropping, and contributed to a

positive nutrient balance, improved soil fertility and increased

income.

REFERENCES

Huynh Duc Nhan, Nguyen Duong Tai, Tran Duc Toan, Thai Phien and Nguyen Tu Siem. 1995.

The management of acid upland soils for sustainable agricultural production in Vietnam:

I. Tarn Dao site. IBSRAM, Bangkok, Thailand.

Thai Phien, Luong Duc Loan, Nguyen Van Truong, Dau Cao Loc and Nguyen Thi Dan. 1994.

The management of sloping land for sustainable agriculture in Vietnam. IBSRAM, Bangkok,

Thailand.

Thai Phien, Nguyen Tu Siem and Nguyen Cong Vinh. 1995. The management of acid upland soil

for sustainable agricultural production in Vietnam: II. Hoa Son site. IBSRAM, Bangkok,

Thailand.

280

PROGRESS IN AGRONOMY RESEARCH IN INDIA

C.R. Mohankumar1, V.P. Potty1, C.S. Ravindran\ S. Kabeerathummd

and C.R. Sudharmai Devi1

ABSTRACT

Nutritional studies of cassava have shown that in high-P acid laterite soils, there was no

response to P application during four years of consecutive cropping. In low-P soil, even though

cassava initially responded to 100 kg P2O5/ha, the response gradually declined. The optimum

economic dose of P for cassava in acid laterite soil is about 45 kg P2O5/ha. Studies on the NPK

requirement of a short duration variety of cassava in a rice-based cropping system, showed that

there was a response to the application of 100 kg each of N and K2O/ha, but no significant

response to P.

In upland rice fields the sequential cropping of vegetable cowpea and cassava can

eliminate the need for FYM application by incorporating the crop residue of vegetable cowpea

before planting cassava.

Application of N and K had a significant effect on root yield of short-duration (7 months)

lines of cassava, CI-649 and CI-731, up to 75 kg N/ha and 100 kg K2O/ha. Studies conducted

by Kerala Agric. Univ. have shown that up to 50% of the KC1 requirement of cassava can be

substituted by sodium chloride (NaCl) without any deleterious effect on crop yield. Another study

revealed that under partial shade of adult coconut palms (76% PAR), rainfed cassava (cv Sree

Visakham) yielded 77 % of that grown in the open.

Transplanting of rooted cassava cuttings, inoculated with the VA-mycorrhizal fungus

(VAMF) Glomus microcarpum var. microcarpum, was found to enhance the total dry matter and

root yield, besides increasing the concentration of micronutrients like Cu and Zn in the leaves.

Mass inoculation with VAMF in farmers' fields by planting rooted infected cuttings showed that

70% of the farmers were convinced that they could obtain a higher yield of roots using this

practice.

The present practice of planting cassava is to plant stakes directly in the field with the

onset of pre-monsoon rains. In this practice, the uncertainty of rainfall may cause poor

establishment. In order to overcome this, cassava stakes are first planted in a nursery at a very

close spacing of 4.5 x 4.5 cm so as to accommodate about 500 stakes/m2. Uprooting is easiest

when a saw dust media is used in the nursery. Root yield was not affected by the time of

uprooting and transplanting in the field between 15 and 25 days, but beyond that age there was

a significant reduction in root yield. This technique can be effectively used when short duration

varieties are grown under rainfed conditions in areas where rainfall is limited to 4 to 5 months per

year. The plants are first raised in a nursery for 25 days and then transplanted in the field with

the onset of rains.

INTRODUCTION

Cassava (Manihot esculenta Crantz), locally known as tapioca, was introduced in

Kerala state of India by the Portuguese in the 17th century. Of the different tropical root

and tuber crops grown in India, cassava is of significant importance since it can produce

more calories per unit of land area. Its importance in tropical agriculture is due to its

1 Central Tuber Crops Research Institute (CTCRI) Triruvananthapuram, Kerala, 695017,

India.

2 Kerala Agricultural University, Thiruvananthapuram, Kerala, 695017, India.

281

drought tolerance/drought avoidance, wide adaptability to diverse soil, nutrient and

management conditions, including the time of harvest. The drought tolerance is mainly

due to the in-built mechanism to shed/drop the leaves under low soil moisture conditions

to facilitate a slow down of all the vital activities of the plant. When soil moisture

increases it again puts forth fresh growth and starts accumulating starch in the storage

roots. Being a photo-insensitive crop, cassava can be profitably cultivated throughout the

year with irrigation.

About 70% of the cassava production in India is used as food, either directly or

in processed forms. The most popular and traditional mode of consumption is in the

form of cooked and mashed roots. After removing the outer rind and inner thread-like

fibrous center core, fresh roots are cut into pieces, cooked in boiling water, decanted and

eaten with fish or coconut gratings. Other methods of consumption are as chips fried in

oil, or sun-dried chips, which are made into flour and used for preparations similar to

those of rice or wheat flours. "Sago" is an important food product derived from cassava

starch. It is consumed as a convalescence food in many parts of India.

In India the cultivation of cassava is mainly confined to the southern states, i.e.

Kerala, Tamil Nadu, Andhra Pradesh and Karnataka, and parts of the north-eastern

regions (Table 1). In Kerala where the annual mean rainfall is about 3000 mm,

distributed over a period of 7-8 months from April-November, cassava is grown under

rainfed conditions. Meteorological data of the major cassava growing states in India are

presented in Figures 1 and 2. In Tamil Nadu where the annual rainfall is only about

1000 mm, distributed over a period of 4-5 months, the crop is grown mainly under

irrigation and with high-input management practices.

Cassava Soils and their Characteristics

In Kerala, cassava is mainly grown on laterite soils (Ultisols), followed by forest

soils (Mollisols) and red soils (Alfisols). In Tamil Nadu, the major soil groups under

cassava are red soils (Alfisols) and black soils (Vertisols). In Andhra Pradesh the

cultivation is mainly confined to the alluvial (Entisols) and red soils (Alfisols). The main

characteristics of these soils are shown in Table 2.

Micronutrient status of cassava soils

A critical appraisal of the availability of micronutrients in the major cassava

growing states revealed that in most cases the soil have micronutrient contents that are

well above the critical limits (Table 3). Inspite of that, there are locations where there

is a response to the application of zinc (Zn). It was noted that Zn availability in laterite

soils did not follow any relationship with the physio-chemical properties of the soil.

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Table 2. Physio-chemical characteristics of the main cassava growing soils in three states of

India.

State Soil type pH Organic CEC Clay content

carbon (%) (me/lOOg) (%)

Kerala Laterite (Ultisols) 4.7-6.2 0.3-2.7 1.4-3.1 11.8-27.8

Red (Alfisols) 4.8-7.0 0.5-1.1 2.0-7.0 12.9-22.4

Forest (Mollisols) 4.5-6.0 0.3-14.7 1.5-19.0 10.6-24.9

Tamil Nadu Red (Alfisols) 8.1-8.7 0.1-1.4 0.5-26.0 11.2-21.8

Black Vertisols) 7.8-8.9 0.3-1.8 2.7-30.0 12.4-21.3

Andhra Pradesh Red (Alfisols) 5.1-7.4 0.1-0.8 2.3-7.0 11.3-15.3

Alluvial (Entisols) 7.2-8.7 0.2-0.8 3.7-4.0 17.8-37.3

Source: Sheeja, 1994.

Table 3. Content of available micronutrients in the main cassava growing soils in three

states of India.

State Soil type Cu Zn Fe Mn B

(mg/Kgj

Kerala Laterite 1.2 0.8 19.3 19.9 0.3

Red 0.6 1.2 12.4 15.1 0.2

Forest 1.2 0.9 43.2 15.7 0.2

Tamil Nadu Red 1.5 1.0 21.4 12.7 0.2

Black 3.2 0.9 6.5 5.7 1.1

Andhra Pradesh Red 1.7 1.1 19.1 20.3 0.2

Alluvial 4.4 0.7 9.5 13.6 0.4

Critical limit (mg/kg) 0.2 0.6 4.5 1.0 0.2

Source: Sheeja, 1994.

284

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285

ANDHRA PRADESH

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286

In about 47% of the surveyed area of black soils of Tamil Nadu, the available

Zn content was below the critical limit and foliar yellowing and low productivity were

noticed. Both red and black soils of Tamil Nadu have a high pH (7.4 and 8.5,

respectively) and Zn availability in these soils was negatively correlated with pH. The

red soils of Andhra Pradesh had comparatively higher levels of available Zn.

Regarding the availability of iron (Fe) all soils had available Fe contents above

the critical limit. In Tamil Nadu red soils had a high level of Fe. The black soils

recorded the lowest content of Fe. Iron deficiency in some parts of these black soils are

due to the calcarious parent material of these soils and, consecuently, a high soil pH

(8.4). Lime-induced Fe chlorosis was observed in black soils of Tamil Nadu. In Andhra

Pradesh red soils had high Fe availability.

With respect to the availability of manganese (Mn), all soils are considered

sufficient in Mn availability. Manganese availability was negatively correlated with pH.

The availability of copper (Cu) in the major cassava growing soils of Kerala, Tamil Nadu

and Andhra Pradesh is also considered adequate as all soils had available Cu contents

above the critical limit.

Nearly all cassava soils in Kerala are low in available boron (B), while red soils

in Tamil Nadu and Andhra Pradesh also have very low levels of B. Nevertheless,

significant responses of cassava to B application have seldom been reported.

RESEARCH RESULTS

A. Cultural Practices for Cassava

1 . Standardization of nursery techniques for cassava

The present practice of cassava planting in traditional areas is to plant the stakes

directly in the field after the receipt of pre-monsoon showers. But in non-traditional

areas, where the rainfall is limited to 4 or 5 months, it is recommended to plant stakes

first in nursery beds at a very close spacing of 4.5x4.5 cm under irrigation during three

weeks before the onset of regular rains. The settlings thus raised in the nursery are

transplanted in the main field with the onset of monsoon rains.

1.1 Effect of nursery medium and time of transplanting

Research results (Table 4) indicate that time of transplanting had significant

effects on root yield. Maximum root yields were obtained when 20 day old settlings

were transplanted in the main field. The type of rooting media had no significant effect

on root yields.

The main advantages of the nursery technique are:

1 . Settlings expressing symptoms of cassava mosaic disease can be discarded in the

nursery itself, thereby greatly reducing the incidence of mosaic in the main field.

2. As the settlings are raised prior to the rainy season and transplanted to the main field

287

with the onset of the monsoon rains, the crop can more effectively utilize the short

rainy season for growth and yield. This is especially advantageous in areas

having a very short rainfall period.

3. In areas where the crop is raised under irrigation, this technique can reduce the

number and quantity of irrigation to the crop.

4. When stakes are planted directly to the main field about 10% of the stakes may fail

to germinate. This technique will reduce the percentage of failure in the main field.

5. Transplanting of healthy and uniform-sized settlings generally results in a more

uniform crop stand in the main field.

1.2 Effect of stem portion and stake treatment

A study was conducted to determine the effect of stem portion and treatment of

nursery-grown stakes on the root yield of cassava. Stakes collected from the bottom 1/3,

middle 1/3 and top 1/3 portion of the stem were treated with either VA-mycorrhizal fungi

(VAMF), plant protection chemicals, 2% zincsulfate solution or 50 ppm IBA. Water-

treated stakes were used as control. The stakes thus treated were planted in the nursery

and 25 day old settlings were transplanted in the main field.

The results (Table 5) indicate that there was no significant difference in yield

due to stake treatment. Regarding the stem portion, cuttings derived from the bottom and

middle portion of the stem were significantly superior to those obtained from the top

portion. From this study, it is concluded that while selecting planting material, stakes

derived from the bottom and middle portion (lower 2/3 length of the stem) are superior

to those from the top part.

1.3 Field trial of rooted infected cuttings

The production of rooted infected cuttings using different media like sawdust,

sand and polypack with garden mixture were assessed. The sawdust was found to be the

best medium. Among dates of transplanting, the 25th day seemed to be good compared

to the 20th day of transplanting.

2. Sequential cropping with vegetable cowpea

The recommended dose of farm-yard manure (FYM) to be applied to cassava is

12 t/ha. In order to substitute for this high dosage of FYM a short-duration leguminous

crop of vegetable cowpea was grown preceding cassava, both under lowland and upland

conditions.

Under lowland conditions, vegetable cowpea followed by cassava was found-to

be a feasible alternative to the use of FYM. The yield reduction under such conditions

was only 12% when compared to the control, where there was no preceding crop of

vegetable cowpea (Table 6). The vegetative matter produced by the seasonal crop was

sufficient to provide enough organic matter to cassava; however, under upland

288

conditions, the cassava crop that followed vegetable cowpea suffered from a root yield

reduction of 30%. The significant reduction in yield was due to moisture deficiency as

a result of late planting and subsequent drought affecting the crop at the root bulking

stage. When cassava was planted in May, up to the harvest of the crop in December,

there was no serious moisture stress, as the crop was receiving the monsoon rains both

for growth and yield.

3. Influence of photosynthetically active radiation (PAR) in intercropped cassava

A trial was conducted at the Kerala Agricultural University to study the influence

of PAR on the root yield of cassava grown as an intercrop under coconut trees during

1992/93 and 1993/94. Cassava was grown as an intercrop under the partial shade of

about 40 year old coconut palms planted at a spacing of 7.5x7.5 m. The planting

patterns of the cropping systems used are shown in Figure 3. PAR incidence on the

cassava canopy was measured at monthly intervals with the help of a line quantum

sensor. PAR received on the canopy of the intercropped cassava was less (76%)

compared to cassava grown under full sunlight (Figure 4). During the rainy months not

much variation was noticed between the quantum of PAR under shaded and open

conditions, whereas in the dry months the PAR received in the open was considerably

higher than that in the shaded area.

The root yield of cassava grown under the partial shade of coconut palms was

less (68%) compared to cassava grown in the open (Table 7). As the shade was more

or less uniform in the coconut garden, no significant differences in cassava root yield

were observed due to the various crop combinations.

B. Soil Fertility Management

1. Long-term effect of manures and fertilizers in acid cassava growing soils

Table 8 shows that increased cassava yields were obtained with an increase in

the level of fertilizer application. Among different nutrient levels, the highest yield was

obtained with 125:50:125 kg/ha of N, P2O3 and K20, in addition to 12 t/ha of FYM.

This treatment was not significantly different from 100:50:100 + FYM. Application of

FYM had a significant effect on yield. Application of the recommended dose of N, P205

and K2O, i.e 100:50:100 kg/ha but without the recommended dose of 12 t FYM/ha,

resulted in significantly lower yields. Sources of P, i.e. triple superphosphate or

Mussorie phosphate, had no significant effect on yield. Application of Zn with the

recommended rate of NPK gave a significantly higher yield.

289

Table 4. Effect of nursery media and time of transplanting of settlings in the main field

on cassava root yield (t/ha) at CTCRI, Trivandrum, Kerala, India.

Rooting Time of transplanting of settlings in the main field (days)

media

10 15 20 25 30 Mean

Sawdust 25.5 26.7 26.1 24.0 22.6 25.0

Sand 27.8 26.6 27.1 24.5 21.9 25.6

Pot mix 25.2 26.5 28.3 24.5 20.3 25.0

Direct planting 25.0 25.5 26.7 23.2 18.6 23.8

Mean 25.9 26.3 27.1 24.0 20.8 -

CD(5%): media NS; time 2.588

Source: Mohankumar, 1993.

Table 5. Effect of stem portion and various treatments of nursery-planted stakes on cassava

root yield (t/ha) in the field at CTCRI, Trivandrum, Kerala, India.

Stakc treatments Top

Stem portion

Middle Bottom Mean

VA-mycorrhizal fungi

PPC (Plant protection chemicals)

Zinc sulfate (2% solution)

IBA (50 ppm)

Control (water)

Mean

27.1 30.2 30.1 29.1

27.4 29.3 30.0 28.9

28.3 30.1 30.5 29.6

27.9 29.4 30.3 29.2

28.1 30.3 30.1 29.5

27.8 29.9 30.2 .

CD(5%): stake treatment NS; stem portion 0.466

Source: Mohankumar and Potty, 1994.

290

Table 6. Biomass production of vegetable cowpea and root yield (t/ha) of subsequently grown

cassava as compared to the root yield of cassava grown without cowpea under

upland and lowland conditions at CTCRI, Trivandrum, Kerala, India.

Crop (date of planting-harvest) Lowland Upland

Vegetable cowpea-cassava

Biomass of vegetable cowpea (May-July)

Root yield of cassava (July-Febr)

Root yield of cassava alone (May-Dec)

20.5 9.1

51.1 23.5

58.0 33.1

Source: Mohankumar and Nair, 1996.

Table 7. Root yields of cassava grown in various intercropping systems in a coconut garden,

as compared with that of monoculture cassava grown in full sunlight at Kerala

Agric. Univ., Trivandrum, Kerala, India

Cropping systems"

Cassava root yield(t/ba)

1992/93 1993/94 Average

1. Co+ Ca

2. Co + Ca+Vcp

3. Co + Ca+EFY

4. Co+Ca+Ba

5. Co +Ca + Vcp +EFY + Ba

Mean

CD(5%)

SEM +

25.01 19.43 22.22

19.75 20.11 19.93

29.79 31.56 30.67

27.32 22.26 24.79

30.20 29.21 29.70

26.41 24.51 25.46

NS NS

2.642 3.247

6. Cassava monoculture (full sunlight) 35.38 30.23 32.80

hCo = Coconut, Ca = Cassava, Vcp = Vegetable cowpea,

EFY = elephant foot yam; Ba = banana

Source: Ravindran, 1996.

291

Table 8. Effect of annual applications of manures and fertilizers on the root yield of the sixth

successive crop of cassava grown in an acid Ultisol at CTCRI, Trivandrum, Kerala,

India.

Treatments" Root yield (t/ha)

50:25(S):50 + FYM 21.7

75:37.5(S):75 + FYM 24.4

100:50(S):100 + FYM 29.4

125:50(S):125 + FYM 30.4

50:25(M):50 + FYM 19.1

75:37.5(M):75 + FYM 20.4

100:50(M):100+FYM 25.1

125:50(M):125 + FYM 31.8

100:50: 100 (noFYM) 18.3

100:50: 100+ 1/2FYM 23.3

100:50: 100+crop residue incorporated (no FYM) 25.9

100:50: 100 + Zn (12.5kg Zn2 SO4) (no FYM) 31.1

Ash+FYM 15.5

Ash+crop residue incorporated (no FYM) 10.2

CD(5%):5.65

"(S)=Triple superphosphate; (M)= Mussorie rock phosphate; FYM= 12 t/ha of farm yard manure

Source: Kabeerathumma and Ravindran, 1996.

292

A. COCONUT B. COCONUT+ CASSAVA

C. COCONUT+CASSAVA+ VEGETABLECOWPEA D. COCONUT+CASSAVA + ELEPHANTFOOT YAM

E. COCONUT+ CASSAVA + BANANA

[90cm

• * ******

coconut

cassava

F. COCONUT+CASSAVA + BANANA +

ELEPHANT FOOT YAM + VEGETABLE COWPEA

O elephant foot yam

0 banana

vegetable cowpea

Figure 3. Planting patterns of component crops in various coconut-based intercropping

systems.

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2. Phosphorus requirement under upland conditions

Under upland conditions of acid lateritic soils of high-P status, skipping of P

application for the first four years had no significant effect on cassava yield. In low-P

soils, even though cassava responded initially to 100 kg P205/ha, the response gradually

declined. The optimum economic dose of P for cassava in acid lateritic soils was

determined to be about 45 kg P205/ha (Nair et al., 1988).

3. Fertilization of short-duration varieties of cassava in a rice-based cropping system

3. 1 NPK requirements

The common cropping system in a single crop rice field under upland conditions

in Kerala is to grow a single crop of dry-sown paddy during the wet season (June-Sept);

afterwards the land is left fallow or rice is followed by a pulse crop. Farmers are forced

to adopt this system due to a lack of irrigation facilities to raise a second crop of rice.

Cropping system studies conducted at CTCRI have shown that a short-duration

(early-maturing) variety of cassava, "Sree Prakash", with seven month duration can be

grown successfully in a rice-based cropping system. In order to standardize the NPK

requirement of Sree Prakash grown under this system, a study was carried out with three

levels of nitrogen (50, 100, 150 kg/ha), three levels of P205 (25, 50, 75 kg/ha) and three

levels of K20 (50, 100, 150 kg/ha) after the harvest of wet season rice.

Table 9 shows that application of 100 kg N/ha increased the yield significantly

over 50 kg/ha. A further increase in N did not show any further positive response.

There was no significant response of cassava to P application in this rice-based cropping

system. Application of K at 100 kg K,0/ha showed a significant improvement in yield

over 50 kg/ha, but this yield was not significantly different from that at 150 kg/ha. The

combined effect of N and K was also significant. However, additional increases in the

level of N and K beyond 100 kg/ha did not produce any significant effect on yield.

From the study it could be concluded that the variety "Sree Prakash" responded

to a fertilizer dose of 100 kg N, 25 P205 and 100 K20/ha in this rice-based cropping

system.

3.2 N and K requirements

Two promising pre-released accessions of cassava, i.e. CI-649 and CI-731 of

seven months duration were tested for standardizing the N and K requirements in a rice-

based cropping system.

The first rainy season crop was rice followed by short-duration cassava. A

short-duration rice was grown during the wet season. "Sree Prakash", a released short-

duration cassava variety was used as a control with a fertilizer dose of 75:50:75 kg of N,

P205 and K20/ha. Two short duration accessions of cassava, CI-649 and CI-731, were

tested under three levels of N and K.

295

Table 9. Effect of levels of N, P and K application on the root yield (t/ha) of cassava, cv Sree

Prakash, grown after rice under lowland conditions at CTCRI, Kerala, India.

"25 "so '75 K50 Kioo K-150 Mean

Njo 34.0 32.8 33.4 31.1 33.8 35.2 33.4

N100 36.8 40.2 38.3 34.5 40.7 40.1 38.4

N150 37.5 39.0 38.2 36.2 38.5 40.2 38.3

Mean 36.1 37.3 36.6 33.9 37.7 38.5

CD (5%) N = 1.385; K = 1.385; P not significant

Source: Mohankumar et al. , 1996.

The cassava variety CI-649 recorded a mean yield of 30.53 t/ha, which was

significantly superior to that of CI-731 or the released variety Sree Prakash.

Tables 10 and 11 show that the application of N had a significant effect on root

production. The highest yield was recorded at 75 kg N/ha, which was significantly

superior to that at 50 kg N/ha, but not significantly different from that at 100 kg N/ha.

Tables 10 and 12 show that application of K had a significant effect on root

yield. The highest yield was obtained with the application of 100 kg K20/ha, which was

significantly superior to that at 50 or 75 kg K20/ha. Highest root yields of both varieties

were obtained with 75 kg N and 100 K20/ha.

4. Effect of fertilization on the yield of triploid cassava

4.1 Effect of NPK

Some of the triploid cassava varieties developed have given higher yields and had

higher dry matter contents than diploids. In order to suggest a suitable fertilizer

schedule, the triploids were grown under three levels of fertilization. The results are

presented in Table 13.

The triploid variety 2/14 recorded the highest yield of 25.58 t/ha, which was

significantly superior to that of 9/76, but not significantly different from that of 237/84.

Regarding levels of fertilizer, the dose of 75:50:75 resulted in a significantly higher yield

than that of 50:25:50, but was not significantly different from 100:50:100 kg/ha of N,

P2O5 and K20.

296

Table 10. Effect of various rates of N and K application on the root yield (t/ha) of two

short-duration lines and a released variety of cassava grown in lowland soils at

CTCRI, Trivandrum, Kerala, India.

Fertilizer levels(kg/ha)

NiKjO."

Variety

CI-649 CI-731 Sree Prakash

(control)

27.8 27.7 .

29.3 27.0 -

31.7 27.6 -

30.7 28.8 -

29.7 28.2 27.2

33.5 31.0 -

30.5 28.8 -

29.8 29.1 -

31.7 29.4 -

50:50

50:75

50:100

75:50

75:75

75:100

100:50

100:75

100:100

Mean 30.5 28.6

CD (5%):variety 0.77; CD: Control vs treatment 2.33

"P was constant at 50 kg P2O5/ha


Table 11. Average effect of various rates of N on the root yield (t/ha) of two short-duration

cassava lines grown in lowland soils at CTCRI, Trivandrum, Kerala, India.

Levels of N (kg/ha)

Cassava lines 50 75 100 Mean

CI-649

CI-731

Mean

29.6"

27.4

28.5

31.3

29.3

30.3

30.7

29.1

29.9

30.5

28.6

CD(5%):0.95

°Date are average values for three levels of K; P was constant at 50 kg P2Os/ha


297

Table 12. Average effect of various rates of K on the root yield (t/ha) of two short-duration

cassava lines grown in lowland soils at CTCRI, Trivandrum, Kerala, India.

Levels of K20 (kg/ha)

Cassava lines

CI-649

CI-731

Mean

CD(5%):0.95

"Data are average values for three levels of N; P was constant at 50 kg P202/ha

Source: Mohankumnar, 1996.

50 75 100 Meat

29.6" 29.6 32.3 30.5

28.4 28.1 29.3 28.6

29.0 28.9 30.8 _

Table 13. Effect of fertilizer rates on the yield (t/ha) of three triploid cassava varieties grown

at CTCRI, Trivandrum, Kerala, India.

Triploid

Fertilizer rate (N:P2O5:K2O in kg/ha)

cassava varieties 50:25:50 75:50:75 100:50:100 Mean

9/76 22.78 23.25 24.64 23.56

2/14 23.61 25.95 27.18 25.58

237/84 24.50 25.61 25.48 25.20

Mean 23.63 24.94 25.77 -

CD(5%):0.953


298

4.2 Effect of lime application

Since some triploids showed foliar symptoms of Ca deficiency, an experiment

was conducted on the potential need for lime application.

The results showed that application of lime had a significant effect on the yield

of all varieties (Table 14). No symptoms of calcium deficiency were noticed, however,

in any of the varieties. The round-shaped leaf lobe of 9/76 was a varietal character and

was observed both in limed and unlimed plots.

Table 14. Effect of lime application on the yield (t/ha) of three triploid cassava varieties as

compared to that of a standand diploid variety grown at CTCRI, Trivandrum,

Kerala, India.

Levels of lime applied (kg/ha)

Triploid

cassava varieties 0 600 Mean

22.53 24.61 23.57

25.08 26.08 25.58

24.00 26.38 25.19

23.87 25.69 -

9/76

2/14

237/84

Mean

CD(5%): 0.78

H- 1687 (control) 19.62 21.87 20.75


5. Substitution of KCI with sodium chloride (NaCI)

5. / Effect on cassava yield

Studies conducted at Kerala Agricultural University have shown that up to 50%

of the K requirement of cassava can be substituted by that of Na by the application of

sodium chloride (NaCI) without any deleterious effect on crop yield (Table 15).

5.2 Effect on nutrient uptake

The uptake of N at different growth stages and with different levels of

substitution of K by Na is shown in Table 16. Up to six months after planting (MAP),

in all the treatments the uptake of N showed an increasing trend and thereafter a decline.

The decline in N-uptake was more conspicuous at 50% substitution of K by Na than in

other treatments. At 2 MAP and 6 MAP, this treatment with 50% substitution recorded

the highest uptake of N. But at harvest time K applied at full dose resulted in the highest

uptake of N.

299

Table 15. Effect of partial substitution of K by Na application on the root yield of cassava

grown at Kerala Agric. Univ., Trivandrum, Kerala India.

Treatments

Root yield (t/ha)

1992/93 1993/94 Mean

21.91 16.70 19.30

19.05 20.30 19.70

26.04 24.50 25.30

18.42 17.90 18.20

11.43 15.30 13.40

13.81 18.30 16.10

16.19 17.80 17.00

100% KC1

75% KCl +25% NaCl

50% KCl +50% NaCl

25% KCl + 75% NaCl

100% NaCl

50% wood ash +50% NaCl

50% KHCOj + 50% NaHCO3

CD(5%) 7.87 6.55 3.44

Source: Sudharmai Devi, 1995

Table 16. Nitrogen uptake at different growth stages as affected by partial

substitution of K by Na in cassava at Kerala Agric. Univ., Trivandrum,

Kerala India.

Nitrogen uptake (kg/ha)

Treatments 2 MAP 4 MAP 6 MAP 8 MAP Harvest"

100% KC1 17.08 33.90 70.36 59.73 60.94

75% KCl + 25% NaCl 11.13 48.89 58.81 54.60 45.74

50% KCl + 50% NaCl 18.85 42.30 102.42 49.65 37.01

25% KCl +75% NaCl 14.95 37.39 69.25 50.53 34.93

100% NaCl 10.20 43.32 66.48 53.58 23.97

50% wood ash + 50% NaCl 8.86 57.10 89.36 54.04 30.50

50% KHCO3+50% NaHC03 11.20 33.18 77.25 49.54 36.93

CD(5%) 4.16 NS 22.39 NS 28.40

" At 10 months after planting (MAP).

Source: Sudharmai Devi, 1995.

300

The uptake of P also increased up to 6 MAP and thereafter declined (Table 17).

Treatment differences were significant only at 2 MAP. During most of the growth stages

the highest uptake of P was observed when 50% of the K requirement was substituted by

NaCl.

Table 17. Phosphorus uptake at different growth stages as affected by partial substitution

of K by Na in cassava grown at Kerala Agric. Univ., Trivandrum, Kerala India.

Phosphorus uptake (kg/ha)

Treatments 2 MAP 4 MAP 6 MAP 8 MAP Harvest

100% KC1 1.92 4.36 8.87 8.65 6.27

75% KCl + 25% NaCl 0.61 5.47 7.29 6.32 6.61

50% KCl + 50% NaCl 1.82 5.19 11.14 9.55 7.02

25% KCl + 75% NaCl 1.11 4.65 8.70 7.77 5.00

100% NaCl 0.65 4.84 6.60 7.53 3.09

50% wood ash +50% NaCl 0.71 5.80 10.40 6.62 4.03

50% KHCO3+50% NaHCOj 0.92 3.75 8.14 7.15 4.36

CD(5%) 0.36 NS NS NS NS


At all stages of growth the highest uptake of K was observed in the 50%

substitution treatment (Table 18). At later stages of growth, Na substitution above 50%

or substitution with other alternate sources decreased K uptake.

The Na uptake followed the same pattern as that of K (Table 19). The uptake

increased up to 6 MAP, and thereafter there was a slight decline.

6. Response of cassava to mycorrhizal inoculation

Studies on the effect of inoculation with VA mycorrizal fungi (VAMF) to

nursery-grown stakes clearly showed that plants inoculated with Glomus microcarpum

var. microcarpum and Glomus fasciculatum enhanced total dry matter and root yields,

besides increasing the concentration of micronutrients like Zn and Cu in the leaves

(Figure 5 and Tables 20 and 21).

About 70% of the farmers who participated in the program on field inoculation

of VAMF infected cuttings were convinced of the benefit of mycorrhizal inoculation in

improving the growth and yield of cassava.

C. Present Recommendations for Cassava Production

Table 22 shows a summary of the present varieties and recommended practices

for cassava production in Kerala.

301

Table 18. Potassium uptake at different stages of growth as affected by partial substitution

of K by Na in cassava grown at Kerala Agric. Univ., Trivandrum, Kerala India.

Potassium uptake (kg/ha)


100% KC1 12.44 11.03 46.66 35.35 28.45

75% KCl + 25% NaCl 4.40 18.25 38.00 35.77 38.53

50% KCl + 50% NaCl 12.14 16.49 48.36 37.54 38.76

25% KCl + 75% NaCl 6.44 10.05 29.76 24.33 14.13

100% NaCl 4.06 11.88 18.58 21.96 14.57

50% wood ash + 50% NaCl 3.84 23.34 46.56 31.49 15.95

50% KHCO3 +50% NaHCOj 2.79 10.54 30.56 29.82 14.37

CD(5%) 2.43 NS NS 10.19 17.50


Table 19. Sodium uptake at different stages of growth as affected by partial substitution of

K by Na in cassava grown at Kerala Agric. Univ., Trivandrum, Kerala India.

Sodium uptake (kg/ha)


100% KC1 0.48 2.17 2.76 2.70 1.45

75% KCl +25% NaCl 0.24 2.47 1.96 1.81 1.42

50% KCl + 50% NaCl 1.00 1.68 2.75 2.38 1.65

25% KCl + 75% NaCl 0.63 1.49 3.87 2.92 1.14

100% NaCl 0.62 2.11 2.56 2.40 1.00

50% wood ash + 50% NaCl 0.45 1.94 3.69 2.03 0.98

50% KHCO3 +50% NaHCOj 0.34 1.75 2.82 1.99 1.04

CD(5%) 0.29 NS NS NS NS


302

Table 20. Effect of VA-mycorrhizal inoculation and P application on the P concentration of

various cassava tissues.

Concentration of P in various cassava tissues (%)

Treatments" Root Stem Leaf

0.13 0.10 0.20

0.19 0.15 0.50

0.21 0.25 0.65

0.19 0.30 0.75

MoP0

M,P0

MoP,

M,P,

Mo=no mycorrhizal inoculation; M,= mycorrhizal inoculation

P0=no P added; P,= half the recommended dose of P

Source: Potty, 1993.

Table 21. Effect of VA-mycorrhizal inoculation and P application on the Cu and Zn

concentration of upper leaves of cassava.

Treatments'

Months after inoculation

10>h

A. Zn concentration (mg/kg)

MoP0

M,P,

MoP,

M,P,

145 150 125 100 75

120 140 100 110 70

150 125 100 90 80

150 145 100 90 80

B. Cu concentration (mg/kg)

MoP0

M,P,

MoP,

M,P,

11 12 13 13 14

11 12 13 14 15

9 10 12 13 16

9 11 13 13 17

" Mo = no mycorrhizal inoculation; M, = mycorrhizal inoculation

Po = no P added; P, =half the recommended dose of P

Source: Potty, 1993.

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304

Table 22. Recommended cultural practices for cassava production in Kerala, India in 1996.

Varieties:

duration

Sree Visakham

Sree Sahya

Sree Prakash

Planting time:

Land preparation:

Planting material:

Planting method:

Plant spacing:

Fertilization:

M-4 : excellent eating quality

H-97 : high starch, good cooking quality, 10 months

H- 165 : early(7 months) variety, desease and pest resistent

H-226 : good cooking quality

(H-1687) : good cooking quality, high yield

(H-2304) : high yield, drought resistent, high starch content

(S-856) : early harvestable (6-7months)

April-May or Sept-Oct

mounds of 25-30cm high, or contour ridges of 25-30cm high

select plants free of CMV, cut mature stems, 15-20cm stakes

vertical, 5 cm deep; replant missing hills at soon as possible

90x90 cm for branching varieties; 75x75 cm for non-branching

types

1 0-15t/ha of FYM, incorporated; 1 00 kg N , 45 P2Oy 100K2O/ha;

P all at planting, N and K split at 0 and 45-60 days; only 25 P2O5

if soil is high in P

under lowland conditions FYM can be eliminated if vegetable

cowpea is grown before cassava and its residues are incorporated into the soil

Sprout removal:

Weeding and earthing up:

Intercrop:

Harvest:

retain only two shoots, removing excess sprouts at 30-45 days.

at 45-60 days and 1-2 months later

peanut, french bean, cowpea

at 7-10 months, depending on variety (see above)

FUTURE DIRECTIONS AND THRUST AREAS

1. Standardization of agro-techniques for cassava grown in rice-based cropping systems

It has been observed that in rice fields where no water logging is experienced,

cassava would be a better crop compared to rice. In the present condition of high

labor costs, farmers are eagerly looking for a less labor-intensive crop like cassava.

It is therefore necessary to standardize the agro-techniques for cassava in a rice-based

cropping system.

2. Cassava as an intercrop with perennials trees

Early bulking, short-duration varieties can be tested under different plant

density/geometry, so as to determine the best planting arrangement when intercropped

305

under perennial trees.

3. Cassava leaves as a source of animal feed

The high-yielding varieties with high rates of leaf production may be tested under

varying levels of inputs to identify varieties suitable for the animal feed industry.

Prunning of tops may be intensified to monthly intervals starting from the 7th month

to the 15th month to determine whether a regular supply of biomass for cattle feed can

be obtained.

4. Rapid multiplication of disease-free planting material

It was found that a rapid propagation method of growing mini-setts in the

nursery, and transplanting to the main field, was very effective as compared to the

cumbersome method of tissue culture. The technique needs to be popularized among

farmers also for the elimination of virus diseas

5. Identification of short-duration high yielding varieties of cassava.

Short-duration varieties of cassava are in high demand among farmers to fit in

a rice-based cropping system, especially in areas where the 2nd crop of paddy is not

remunerative due to lack of an assured source of water for irrigation.

6. Studies on the effect of cassava intercropping in reforested areas on soil nutrients,

surface runoff and soil loss

Wherever reforestation is initiated, cassava may be introduced as a companion

crop in the first 2 or 3 years, which will give additional income to the government.

No detailed studies have been carried out on the impact of interplanting of cassava

with forest species. A detailed study is required to find out the changes that are

taking place in the flora and fauna of the ecosystem, the soil nutrients, surface runoff

and soil erosion loss as the land is of varying topography.

7. Integrated nutrient management for sustainable crop production by complementing

chemical fertilizers with green manures and biofertilizers

8. Identification of varieties for non-traditional areas

At present, the area under cassava in non-traditional areas is increasing as the

cassava roots constitute the raw material for various industrial products, such as

starch, sago etc. So, suitable agro-techniques have to be developed for popularizing

cassava cultivation in non-traditional areas. Wherever irrigation facilities are

available, irrigation experiments have to be initiated to determine the water

requirement.

9. Regional trials

Location-specific trials have to be undertaken in different agro-climatic zones,

so as to identify varieties better suited to various agro-ecological conditions.

REFERENCES

Kabeerathumma, S. and C.S. Ravindran. 1996. Long-term effect of manures and fertilizers in acid

Ultisol growing cassava. Annual Report, Central Tuber Crops Research Institute, Trivandrum,

India.

306

Mohankumar, C.R. 1993. Standardisation of nursery techniques for cassava and sweet potato.

Annual Report, Central Tuber Crops Research Institute, Trivandrum, India.

Mohankumar, C.R. 1996. Standardisation of agronomic requirements for advanced breeding lines

of cassava. Annual Report, Central Tuber Crops Research Institute, Trivandrum, India.

Mohankumar, C.R. and P.G. Nair. 1993. Standardisation of agronomic requirements for hybrid

selections of cassava. Annual Report, Central Tuber Crops Research Institute, Trivandrum,

India.

Mohankumar, C.R. and V.P. Potty. 1994. Effect of set treatment on yield of cassava. Annual

Report, Central Tuber Crops Research Institute, Trivandrum, India.

Mohankumar, C.R. and P.G. Nair. 1996. Dry matter production and nutrient uptake (NPK) in

a tuber crop-based cropping system under upland rice situations. In: Tropical Tuber Crops.

Problems, Prospects and Future Strategies. Oxford and IBH publishing Co. Pvt. Ltd. New

Delhi 110015, India. pp. 100-206.

Mohankumar, C.R. , P.G. Nair and P. Saraswathy. 1996. NPK requirement of a short-duration

variety of cassava in a rice-based cropping system. In: Tropical Tuber Crops. Problems,

Prospects and Future Strategies. Oxford and IBH publishing Co. Pvt. Ltd. New Delhi 1 10015,

India. pp. 233-237.

Nair, P.G., B. Mohankumar, M . Prabhakar and S.Kabeerathumma. 1988. Response of cassava

to graded doses of phosphorus in acid laterite soils of high and low P status. J. Root Crops

14(2): 1-9.

Ravindran, C.S. 1996. Nutrient-Moisture-Light Interactions in a Coconut-based Homestead

Cropping System. Ph.D thesis, University of Kerala, Trivandrum, Kerala, India. p.

Potty, V.P. 1993. VA mycorrhizal association in tuber crops and their role in crop nutrition.

Annual Report, Central Tuber Crops Research Institute, Trivandrum, India. pp.

Sheeja, S. 1994. Micronutrient Status and their Distribution in Major Tuber Crop Growing Soils

of India in Relation to Soil Properties. Ph.D thesis, Kerala Agricultural University,

Trivandrum, Kerala, India. p.

Sudharmai Devi, C.R. 1995. Partial Substitution of Muriate of Potash by Common Salt for

Cassava (Manihot esculenta Crantz) in on Oxisol of Kerala. Ph.D thesis, Kerala Agricultural

University, Trivandrum, Kerala, India. p.

307

RECENT PROGRESS IN CASSAVA AGRONOMY RESEARCH IN INDONESIA

J. Wargiono1, Kushartoyo2, Suyamto H.2, and B. Guritnd'

ABSTRACT

Annual growth of cassava production in the main cassava production areas during the last

five years seems to have kept pace with the increase in population, while the harvested area of

cassava increased only 0.6% annually. Of the total cassava produced, about 54% is used for

human food, 28% for industrial purposes, 2% for feed and 16% for export. Therefore, the

development of this crop should be in line with the development of other food crops and agro-

industry, as well as with that of dried casssava for export.

Of the total cassava area planted in the country, more than 60% is harvested during June

to October. Delaying the planting of both cassava and the intercrops tends to give a similar gross

return compared to that of planting in the early rainy season. Therefore, most farmers in Sumatra

are now planting cassava from the early rainy season to the early dry season. Thus, the cassava

harvest is more spread out and cassava becomes a more dependable crop for both the starch and

pellet industries, as well as a food security crop in rural areas. Most farmers do not fertilize

cassava due to lack of capital; therefore, a closer cooperation between the farmers and starch and

pellet factories should be considered to solve this problem.

Cassava agronomy research is mainly conducted by the Bogor and Malang Research

Institutes for Food Crops, by Brawijaya University in Malang and by the Umas Jaya cassava

plantation in Lampung.

The yield of both cassava and intercrops grown on an ultisol in Lampung decreased more

than 60% during the third consecutive cropping without any fertilizer application. Interplanted

crops like maize, rice and peanut grow faster than cassava and the amounts of nutrients absorbed

by these crops during the first two months are higher than for cassava under these intercropping

systems. But, there is an indication that cassava absorbs residual fertilizer applied to these

interplanted crops. Crop productivity could be maintained by the application of adequate amounts

of fertilizer and by the incorporation of cassava stems and leaves into the soil. A balanced

fertilizer rate of 75-100 kg N, 25-100 kg P2O5 and 60-100 kg K2O/ha for monoculture cassava and

100-150 kg N, 50-100 kg P2O5 and 100-150 kg K2O/ha increased net income by 70 and 370% and

reduced erosion by 11 and 35%, respectively.

Soil loss due to erosion in monoculture cassava during 10 months in Malang, E. Java,

was more than 50 t/ha of dry soil. Fertilizer application, ridding, elephant grass strips and

intercropping decreased the amount of eroded soil significantly, compared to monoculture cassava

without fertilization. Cassava clones with wide leaves and no branching are considered suitable

for intercropping systems.

INTRODUCTION

Indonesia has the fifth highest cassava production in the world. Annual

production is quite variable, fluctuating from 15.8 million tons in 1990, 17.3 million tons

in 1993 and 15.7 million tons in 1994 (Table 1). This fluctiation is caused by

fluctiations in prices for cassava products both in Indonesia and in other cassava

1 Research Institute for Grain Legumes and Tuber Crops (stationed in Bogor, W. Java).

2 Research Institute for Grain Legumes and Tuber Crops, Malang, E. Java.

Brawijaya University, Malang, E-Java.

308

producing countries. Higher prices of pellets and chips, both inside and outside the

European Union countries, as well as in the Indonesian market, stimulate cassava

production in the following season. Then, the increase in cassava production always

brings about a decrease in price. This low price discourages farmers from growing

cassava in the next season. These price fluctuations should be minimized through the

development of more rural agro-industry and food processing as well as through greater

diversification of end markets.

Table 1. Cassava area, yield, production and export in Indonesia, as well as prices of pellets and chips

in the EEC and outside the EEC Market from 1990 to 1994.

Year Harvested

area(.OOOha)

Yield

(t/ha)

Production

COOOt)

Total

exported

Prices($/ton)

COOOt)

In EEC Outside EEC

Chips Pellets Chips Pellets

1990 1,311 12.07 15,830 1,009 118 124 61 98

1991 1,319 12.10 15,955 956 132 138 58 144

1992 1,351 12.23 16,516 932 127 132 72 143

1993 1,402 12.33 17,285 1,150 109 115 52 51

1994 1,357 11.59 15,729 776 93 100 72 50

Source: BINUS, 1995

Of the total cassava produced in Indonesia about 54% is used for human food

(0.83 kg fresh root/day/person), 28% for industrial purposes, 2% for feed and 16% for

export (BINUS, 1995).

Crop and land productivity are the determining factors in the farmers' income.

In Indonesia cassava is mostly grown on marginal upland soils and the average cassava

yield of about 12.2 t/ha is much below the potential yield obtained in experiments, which

ranges from 20-40 t/ha. Therefore, there is still a potential to improve production

technologies in order to increase yields and farmers' income, while at the same time

conserving the soil and water resources.

The main cassava producing areas in Indonesia are located in relatively dry

regions and on marginal soils of Java and Nussa Tenggara, where the crop is grown

mainly by small-scale farmers which have limitations of land, capital and labor.

Consequently, the cassava planting time tends to coincide with the beginning of the rainy

season and cassava is usually intercropped with other food crops. In transmigration areas

of Sumatra and Kalimantan cassava yields and harvested area vary due to limited

availability of labor and capital to grow cassava as well as other food crops. For

cassava to be a dependable crop, both as a staple food and as a cash crop, farmers will

grow cassava depending on the availability of capital and labor in the family, usually

from the early to the end of the rainy season.

Cassava plants absorb large amounts of nutrients from the soil. Therefore,

309

fertilization is often the only way to maintain soil fertility and land productivity. As the

goverment plans to stop subsidizing fertilizers, it means that the price of fertilizers will

increase and farmers will reduce fertilizer applications to cassava.

In Indonesia most cassava plant parts are utilized and removed from the field.

Thus, organic matter additions are also needed to maintain soil fertility in the long-term.

Intercropping cassava with upland food crops not only improves the land use efficiency,

farmers' income and the distribution of this income through the year, but it also adds

more organic matter to the soil than planting cassava in monoculture.

Cassava growth during the first three months is relatively slow. Erosion during

this period is relatively high as the soil surface is not adequately covered by the cassava

plant canopy. Cropping systems and cultural practices that cover the soil more quickly

must be identified to reduce erosion.

During the past ten years, the Bogor and Malang Research Institute for Food

Crops, the Agricultural Faculty of Brawijaya University in Malang, and the Umas Jaya

cassava plantation in Lampung have been conducting cassava agronomy research with

emphasis on solving the above-mentioned problems.

Production Areas and their Agro-ecological Characters

Recent trends in cassava area, production, yield and cassava product prices, as

well as the total amount of cassava exported are presented in Table 1 . Annual growth

rates of cassava production and harvested area from 1990 to 1993 were 3.0 and 2.2%,

respectively. The decrease in harvested area (7.5%) and production (9.0%) in 1994 was

mainly due to drought. Cassava yields were also affected by drought conditions.

Plant productivity is determined by NAR (net assimilation rate), where NAR

depends on soil conditions and water availability (Hozyo et al., 1984). Cassava root

yields decreased significantly when 2-4 months before the harvest the top soil became

hard due to drought (Wargiono, 1993). During the 1993/94 cropping season, rainfall

during the 3rd to 5th month after planting was substantially lower than during the same

period in the 1992/93 season. This resulted in considerably lower yields in 1994 in all

production zones except in Kalimantan (Figure 1).

Limited availability of capital is one of the constraints for the farmer to fertilize

his cassava crop and to maintain land productivity. Since cassava absorbs large amounts

of nutrients from the soil, the application of farm yard manure (FYM) or fertilizers have

to be considered. Limited labor in the family is another production constraint and

farmers may need to rent a tractor for land preparation and use herbicides to control

weeds.

More than 60% of cassava production is located in Java and the remaining 40%

mainly in Sumatra, Nussa Tenggara and in the Sulawesi islands. Most cassava in Java

is planted in the early rainy season due to limited arable land, whereas in Sumatra land

holdings are larger, generally more than one ha, so cassava is planted from the beginning

310

to the end of the rainy season. The wider spread of cassava planting time is one

alternative to reduce temporary over-production (Wargiono, 1993). Since the delay in

cassava planting time is possible in Sumatre due to a longer wet season, cassava

production in Lampung is better distributed throughout the year compared to that in Java

(Wargiono et al., 1995).

Cassava in Indonesia is grown on a variety of soils, such as Alfisols, Ultisols,

Entisols, Inceptisols, Vertisols and various soil complexes (Wargiono, 1988). These soils

are usually infertile and are often susceptible to erosion. Therefore, better soil

conservation technologies, which are able to maintain or improve land productivity and

are acceptable to farmers, are urgently needed.

RECENT CASSAVA AGRONOMY RESEARCH

Cassava agronomy research in Indonesia has as its main objective to increase

cassava yields and farmer income while maintaining or improving soil fertility and land

productivity. The research, therefore, includes the identification of cassava production

constraints, the evaluation of new cassava clones under intercropping systems, the control

of erosion, and the improvement of cultural practices and fertilizer use efficiency.

1. Case Study to Determine Cassava Production Constraints

A study was conducted in Nov 1995 in transmigration areas of northern

Lampung. The sub-districts studied were Manggala, Tulangbawang Udik, Tulangbawang

Tengah and Mesuji.

Cassava in this area is a staple food, consumed as steamed cassava/rice pellets

(tiwul) during 3 to 9 months of the year. Tiwul is made from cassava flour mixed with

rice in a ratio of 2-4: 1. Based on an average cassava flour consumption of 0.33

kg/day/person, the cassava consumed as tiwul is about 25 kg fresh roots/month/person.

Table 2 shows supply and demand of cassava in the sub-districts studied, where

utilization for human food and industrial purposes were only 9.3% and 32.3%,

respectively. Table 3 shows cassava yield and production during 1990-1994 in the sub-

districts studied. In some cases production increased in spite of a decrease in yield; this

is due to a marked extension of planted area. This production was affected by demand

by the industries and by availability of infrastructure. Good infrastructure reduces

transportation costs and facilitates the sale of cassava. Therefore, the farmgate cassava

price of these areas is higher compared to those in areas with poor infrastructure.

The cropping system used in this area is affected by the availability of labor and

capital. Average available labor is two persons per family. The capability of these two

laborers to prepare land and grow food crops was 0.25-0.5 ha/month. Therefore,

farmers have to delay land preparation and the planting of food crops when they want to

grow crops on more than 0.5 ha.

311

15 r

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11.6 11.4

D1993

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9.5

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Java Sumatra Southeast Sulawesi Kalimantan

Indonesia

Figure 1. Cassava yields by region in 1993 and 1994.

Source: CBS, 1995.

The Ultisol soils of the areas studied are mostly infertile; thus fertilization and

good crop management (controlling weeds and pests/deseases) are essential for obtaining

good yields. Since cassava grows better than other food crops on infertile land and with

low inputs, more and more cassava is grown by those farmers that have limited capital.

Table 3 shows that cassava yields decreased dramatically over time in all four sub-

districts. In 1990 the land was newly opened from the bush and high yields could be

obtained without any fertilization. However, cassava extracts large amounts of nutrients

from the soil and soil fertility decreased, resulting in a decrease in cassava yield as no

fertilizers were applied by the farmers in each growing season. With adequate

fertilization high yields of cassava could probably have been maintained (see below). But

most cassava farmers have no money to buy fertilizers; thus, the subsidizing of fertilizers

may still be needed. As fertilizer subsidies from the government will be stopped,

fertilizer subsidies from private companies through a cooperative system with farmers'

groups may have to be considered. A Cooperative Model (Figure 2) with clearly defined

relations between farmers' groups and a tapioca factory, might be recommended.

2. Cropping Systems

Cassava is planted in monoculture only around urban areas, in starch factory

plantations and on non-productive land, which cannot be planted to other food crops.

Most farmers, however, plant cassava intercropped with other food crops, since this will

enable them to increase their land use efficiency and income, improve the soil's physical

312

Table 2. Supply and demand of cassava in various subdistricts studied in northern

Lampung in 1995.

Sub-district Demand(%)

Production

('OOOt)

Surplus

Food Industrial purpose ('OOOt)

Manggala 483.6 5.9 32.7 297.2

T.B. Tengah 137.2 16.4 49.6 46.7

T.B. Udik 111.4 8.5 0 102.0

Mesuji 111.9 16.0 41.8 47.3

Source: Ditpertan, North Lampung 1995

Table 3. Cassava yield and production in four subdistricts of northern Lampung from 1990

to 1994.

Year Manggala T.B.Tengah T.B.Udik Mesuji

Yield Production Yield Production Yield Production Yield Production

(t/ha) (.OOOt) (t/ha) (.OOOt) (t/ha) (.OOOt) (t/ha)(•OOOt)

1990 27.0 326.0 26.3 138.8 23.9 72.9 22.4 222.9

1991 24.7 436.1 23.1 128.2 19.7 162.9 20.2 133.3

1992 21.3 269.7 20.0 80.2 19.5 153.7 20.0 83.1

1993 13.9 503.7 14.2 271.9 13.9 84.5 13.8 89.8

1994 11.9 882.3 12.4 66.8 11.1 83.2 13.4 30.6

Source: Ditpertan, North Lampung, 1995.

condition and reduce erosion, as compared with planting in monoculture (Guritno, 1989;

Wargiono et al., 1992).

Table 4 and 5 show that growing food crops, either in monoculture or in an

intercropping system, without any fertilization is generally not recommended because of

the low yields obtained. Intercropping cassava + maize+ upland rice-peanut may be

recommended because higher total crop values can be obtained compared with

monoculture upland rice, maize and peanut, followed by cassava. In the latter cropping

313

systems, the low yield of cassava (Table 3) is due to drought during the last four months

and the harvesting of cassava at only 6 months. The higher crop value of the peanut-

cassava system compared to that of upland rice-cassava or maize-cassava is due to the

higher crop value of dry pods of peanut than dry grain of either maize or rice. The

cropping system of peanut-cassava produced a high crop value as well as an effective

control of erosion (Figures 3 and 4). More research of this system is needed before it

can be recommended.

Tapioca

Factory

Agric

Ext.

Field

Staff

Processing

Staff

Field

Assistance

Field

Specialist

Administration

Staff

Production input

(Fertilizer,etc)

Farmers

Group

Farmers

Figure 2. Diagram of Cooperative Model offarmers' group with tapioca factory at

Lampung, Indonesia.

Table 5 shows that the intercropping of cassava + maize+ upland rice-soybean

increased net income 17% compared to that of monoculture cassava, while the LER of

this intercropping system was 1.44. Monoculture plantings of upland rice-soybean,

maize-maize, peanut-peanut or soybean-soybean usually yielded a higher net income than

the intercropping system of cassava + maize+ upland rice-soybean. For farmers having

314

land that is very susceptible to erosion, intercropping systems are still recommended since

these systems tend to control erosion more effectively.

Table 6 shows the performance of various cassava clones and the corresponding

interplanted crops. Some characteristics of Adira 1 are the lack of branching short

maturity and narrow canopy diameter, which favor high yield of interplanted crops due

to the low competition from cassava. The average land holding of most farmers in Java

is relatively small; thus, high yields of both cassava and interplanted crops are expected

to enhance food diversity and increase farmers' income. UB1-2 is another cassava clone

well suited for intercropping systems.

3. Erosion Control by Cultural Practices

In Indonesia cassava production areas are mainly located in mountainous areas

of Java and in regions of undulating topography outside of Java. In Java land holdings

are relatively small and erosion could be reduced substantially by terracing; however, this

is still very expensive. Land holdings outside of Java tend to be larger, so reducing

erosion by terracing is too expensive and this method is seldom practiced by the farmers.

Soil erosion, which is the main cause of soil degradation (Suwardjo and Sinukaban,

1986), can also be reduced effectively by cultural practices, such as contour ridging,

contour barriers/hedgerows, mulching and minimum tillage (Evangelio et al., 1993;

Sittibusayaera/., 1993; and Wargiono, 1993).

Table 7 shows that soil erosion varied markedly from year to year but was

consistently higher in unfertilized than in fertilized plots. Erosion losses could also be

reduced by contour ridging, by intercropping with peanut or the planting of a covercrop

of Mimosa envisa; however, the latter markedly reduced cassava yields, which is

probably unacceptible to farmers. Most effective in reducing erosion, while also

increasing cassava (and sometimes maize) yields, was the establishment of contour

hedgerows of Gliricidia sepium or Flemingia congesta. When the pruned leaves and

branches of these leguminous trees were mulched between cassava plants, they obviously

supplied additional N to the crop, resulting in greener and more vigorous cassava plants.

The beneficial effect of these hedgerows increased over time. Contour barriers of

elephant grass were also quite effective in reducing erosion and increasing yields as long

as the elephant grass was adequately fertilized. This system also provides a regular

supply of feed for the farmer's animals. A similar trial conducted on a farmer's field

with 10% slope in Tarokan village of Kediri district (Table 8) also shows that

intercropping cassava with peanut and planting contour barriers of elephant grass was the

most effective way to increase cassava yields and reduce erosion. This system is easier

and cheaper to implement than the terracing system.

Fertilizer application to cassava grown in monoculture or intercropped in an

Ultisol in Lampung not only increased crop value by 56% and 23%, respectively, but

also reduced erosion (Wargiono et al., 1995).

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Table 6. Yields of seven cassava varieties as well as those of intercropped maize, upland rice

and mungbean planted in a C+M+R-Mu system in Playen district of Yogyakarta,

Indonesia in 1994/95.

Cassava Cassava Maize Rice Mungbean Total crop value

Variety (t/ha) (t/ha) (t/ha) (t/ha) fOOORp/ha)"

Adira 1 17.23 2.75 1.01 0.69 2661

Malang 1 21.75 1.71 0.99 0.44 2345

UB 1-2 22.97 2.46 0.98 0.58 2744

UB 1-2/15 23.27 2.14 0.81 0.41 2433

UB 15-10 22.49 2.75 0.76 0.47 2595

UB 881-5 21.39 1.71 1.07 0.56 2465

UB 477-2 22.90 1.86 1.02 0.51 2528

"Prices: cassava fresh roots Rp 50/kg.

rice dry grain 350/kg.

maize dry grain 250/kg.

mungbean dry grain 1,100/kg.

Fertilization usually increases both plant height and canopy diameter. The greater

the canopy diameter of both cassava and interplanted crops the more soil is protected

from the direct impact of falling rain drops and the lower the erosion. Figure 3 shows

that fertilization to monoculture cassava, to upland rice-soybean and to maize-maize

reduced erosion by 35, 11 and 19%, respectively. Eroded soil loss in monoculture

soybean-soybean was as high as in monoculture cassava. Therefore, growing soybean

in areas that are susceptible to erosion have to be reconsidered. On the other hand,

monoculture peanut-peanut controlled erosion very effectively. Similar results were

obtained in a previous trial at the same location, in which only one crop of peanut,

upland rice or maize were grown per year in comparison with monoculture or

intercropped cassava (Figure 4). Based on these results, the development of both

monoculture and intercropping systems with peanut in upland areas which are susceptible

to erosion is recommended.

The effect of agronomic practices on soil losses and crop value, as shown in Table

4, indicate that the intercropping system of cassava+ upland rice + maize-peanut and the

monoculture system of peanut-cassava have a similar crop value and controlled erosion

effectively. Therefore, these conservation cultural practices are also applicable for

farmers having marginal soils in cassava production areas.

4. Fertilization

The efficiency of fertilizer application, or the crop's ability to absorb nutrients, is

affected by the type of soil and the fertilizer applied, the responsiveness of the crop or

variety, the crop's general condition, the cropping pattern and the availability of other

nutrients (Wargiono, 1991; Widjaya et al., 1990).

In Thailand and Indonesia, among the nutrients applied, the effect of N application

on cassava yield was most pronounced, and the response to N increased with each

consecutive cropping cycle, whereas the effect of P and K was only significant in some

locations (Sittibusaya et al., 1993; and Wargiono et al., 1995). Continuous cropping of

318

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600

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Figure 3. Accumulated dry soil loss due to erosion in various crops grown in monoculture

or intercropped, with or withoutfertilizers, on 5% slope in Tamanbogo,

Lampung, Indonesia in 1994/95. The rainfall distribution during the

cropping cycle is shown below. Arrows indicate time ofplanting first and

second crops.

319

cassava; 1.0x1.0 m; with fertilizer

8 + M + R-P; 2.0x0.5 m, no fertilizer

+ M + R-P; 2.73x0.6x0.6 m. no fertilizer

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Figure 4. Effect of various crops, cropping systems and agronomic practices on the

accumulative dry soil loss due to erosion on 5% slope in Tamanbogo,

Lampung, Indonesia in 1993/94. The rainfall distribution during the cropping

cycle is shown below.

320

cassava with application of only chemical fertilizers was able to sustain high cassava

yields in India, but the application of chemical fertilizers with FYM could also maintain

the organic matter as well as the Ca, Mg, Cu and Zn contents of the soil (Nayar et al.,

1995).

Tables 4 and 5 show the fertilization effect on both monoculture and

intercropping systems. Fertilizer application to monoculture cassava, upland rice-soybean

and maize-maize increased gross income by 189, 137 and 371 %, respectively, compared

to that of the unfertilized crops. Fertilization of the intercropping system of cassava +

maize + upland rice-peanut increased gross return by 94 to 129% compared to that of the

same unfertilized intercrops. Since fertilization of either monoculture or intercropping

systems increased net income, often by more than 150%, this is an effective way to

increase farmers' income.

The long-term effect of annual application of N, P and K on cassava yields and

nutrient levels in the soil during eight consecutive cropping cycles in Umas Jaya farm in

Lampung province of Sumatra, is shown in Figure 5. Independent of fertilizer

applications, cassava yields increased during the first two-three years, subsequently

declined, but increased again from the 6th to the 8th year. There was no statistically

significant response to application of any of the nutrients since both P and K levels in the

soil remained near or above the critical levels. Only after four consecutive crops did the

P and K levels decrease slightly below the critical levels and a minor response to these

nutrients was observed in subsequent years. The lack of response to fertilizers in a soil

that is generally considered as an "infertile" Ultisol is attributed mainly to the fact that

after each harvest, plant tops were reincorporated into the soil, while only the nutrients

in the roots were removed from the field. In this way, excessive nutrient extraction was

prevented and soil fertility maintained at a reasonable level. However, with annual

application of intermediate levels of NPK (50-57-60 kg N-P205-K20/ha), high yields of

25-30 t/ha as well as a reasonable level of soil fertility could be maintained for at least

eight years.

Figures 6 and 7 show the results of a similar long-term fertility trial conducted

on an Andosol (Inceptisol) in Jatikerto Experiment Station in Malang in eastern Java.

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Table 8. Effect of various cropping systems on dry soil loss due to erosion and on

the fresh root yield of cassava (cv Adira 4) planted on 10% slope in

Tarokan village of Kediri district in E. Java, Indonesia in 1993/94

Dry soil loss Fresh root yield

Treatments (t/ha) (t/ha)

1. Cassava" monoculture 31.90 16.75 be

2.C + maize 27.54 14.38 a

3.C+peanut 16.60 20.13 d

4.C + 2 rows of elephant grass 23.81 18.25 c

5 . C + Crotalariajuncea intercrop 19.18 15.13 ab

6.C + maize+ 1 row of elephant grass 21.24 15.38 ab

7.C + peanut + 1 row of elephant grass 13.99 23.38 e

8. No crop (bare fallow) 38.09 -

"cassava planted at 1.0x1.0 m, maize 1.0x0.5 m, peanut 0.25x0.25 m,

Crotalaria juncea 1.0x1.25 m.

Source: Soemarjo Poespodarsono and Nur Basuki, 1994.

In this case, cassava was intercropped with maize and all plant tops were removed after

harvest. There was a highly significant response to NPK application already in the first

year. The response to N increased over time, while the response to P and K varied over

the years, but was usually not significant. Although this soil has an intermediate level

of OM (1.2-1.8%), the main cassava response was to N application, which was probably

accentuated by the strong competition from the intercropped maize. Without N, cassava

yields dropped to less than 4 t/ha in the 7th crop cycle. While the soil P level was

slightly below and the exchangeable K was far above the critical level, there was no

response to P but a significant response to K during the 7th consecutive cycle (Figure 7).

The annual application of intermediate and high levels of NPK increased yields from 2

to 23 and 30 t/ha, respectively.

Figure 8 shows the effect of NPK fertilizers on the yield of intercropped cassava,

maize, upland rice and mungbean during the 4th cropping cycle in an Alfisol in

Yogyakarta. A fertilizer application of 90 kg N + 50 P203 + 90 Kj0/ha tended to

maintain low but stable yields of cassava and high yields of interplanted crops during four

years of cropping. The growth of mungbean as a second intercrop (planted after the

harvest of upland rice) was affected by light competition from cassava. Fertilization

stimulated the cassava growth, resulting in an increase in cassava yield but a decrease in

mungbean yield. Fertilization of 90 kg N + 50 P205 +90 K20/ha seemed to be a good

fertilization rate as it maintained both high yields of crops and net income.

Figure 9 shows the effect of NPK fertilization on cassava intercropped with

323

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exchangeable K and available P (Bray 2) content of the soil during ten years

of continuous cropping in Umas Jaya, Lampung, Indonesia.

324

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exchangeable K and available P (Bray 2) content ofthe soil during eight years

of continuous cropping in Jatikerto Experiment Station in Malang, E. Java,

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upland rice and maize in an Ultisol of Lampung during the 4th cropping cycle. Cassava

in this area is an important crop, so cassava is grown in the cropping system with a

higher plant population than is used in Java. As such, the yield of cassava is higher but

the yield of interplanted crops is lower compared to those in Java. Most Ultisols have

relatively low nutrient contents; consequently, crop productivity is low. To obtain a high

net income, the rate of fertilizers applied must be relatively high. In Yogyakarta the

fertilizer application of 90 kg N + 50 P205 + 90 Kj0/ha in the intercropping system of

cassava + maize + upland rice-mungbean yielded a net income of Rp 1 ,900,000/ha,

whereas in Lampung the higher fertilizer rate of 180 kg N + 100 P205 + 190 K2O/ha

yielded a net income of only Rp 900,000/ha.

Based on on-farm research in cassava production areas of southern Malang in

East Java a balanced rate of fertilization for both cassava and intercropped maize (Table

9) increased net income by about 50%. Therefore, a rate of 170-67-60 of N-P2O5-

K20/ha (corresponding to C1-M2 in Table 9) can be recommended when farmers have

access to sufficient capital.

FUTURE PLANS

Some soil conservation practices, such as contour ridging, fertilizer application,

intercropping with peanut and alley cropping with Gliricidia or Flemingia offer good

possibilities to improve farmers' income while reducing soil losses due to erosion.

Which practice is the most beneficial to the farmers still needs to be investigated. There

is also a need to conduct more research about the efficient management of crop residues,

improved fertilizer efficiency and cassava clone performance under specific conditions,

since optimum agronomic practices are different in each agro-ecological zone.

CONCLUSIONS

Most cassava is grown on poor soils that are susceptible to erosion, and where

farmers have limited availability of capital and labor. Intercropping is recommended due

to its capability to reduce erosion, increase LER and net income, and improve food

crop's diversification and support the food security program.

The limited availability of labor and capital of most farmers tend to encourage

the growing of low-input crops, such as cassava, and to delay cassava planting. Better

cooperation with private companies to supply fertilizers and herbicides for their food crop

cultivation is a possible solution.

A balanced rate of fertilizer application, such as 75-100 kg N + 25-50 P2O5 +

60-100 K20/ha for monoculture cassava, and 100-150 kg N + 50-100 P205 + 100-150

K2O/ha for the intercropping system of cassava+ maize+ upland rice-peanut or soybean

is able to increase net income by 70 and 370% and to reduce soil erosion by 11 and

35%, respectively, as compared to that of unfertilized crops. Moreover, adequate

fertilizer application can maintain soil productivity.

328

Table 9. Effect of fertilizer application to cassava and/or maize in cassava/maize

intercropping systems on yield, crop value and net income. Data are average of

three farms in Sempol village, southern Malang, Indonesia in 1991/92.

Treatments" Yield (t/ha) Fertilizer Totalcrop Net

Cassava-Maize cost2'

<

value2)mOORn/ViaV income

cassava maize >

C2-M2 30.73 a 1.20 a 175.50 1716 1541

CI - M2 29.66 a 1.19a 136.25 1661 1525

CO- M2 20.49 c 1.19a 97.00 1203 1106

C2-M1 28.23 b 1.03 b 127.00 1566 1439

CI -Ml 22.87 d 0.99 bc 87.75 1292 1204

CO -Ml 17.56 f 0.94 c 48.50 1019 970

C2-M0 26.01 c 0.61 d 78.50 1392 1313

CI -MO 21.89 de 0.57 d 39.25 1180 1141

CO- MO 18.06 f 0.54 d 0 984 984

" C2 = full recommended dose for cassava = 150 kg urea, 100 kg TSP and 100 kg KCl/ha

CI and Co are half recommended dose and no fertilizer, respectively, for cassava

M2 = full recommended dose for maize = 300 kg urea, 100 kg TSP and 50 kg KCl/ha

Ml and Mo are half recommended dose and no fertilizer, respectively, for maize

:'Prices: cassava fresh roots Rp 50 /kg

maize dry grain 150 /kg

urea 210 /kg

TSP 210 /kg

KC1 260 /kg

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REFERENCES

Central Bureau of Statistics (CBS). 1995. Statistik Indonesia. Produksi dan luas panen

ubikayu. (Production and harvested area of cassava). Jakarta, Indonesia.

Direktorat Bina Usaha Tani dan Pengolahan Hasil (BINUS). 1995. Laporan Temu Asosiasi

Direktorat Bina Usaha Tani dan Pengolahan hasil - ASPEMTI - ATTI (Proc. Meeting

of Association of ASPEMTI and ATTI). Jakarta, Indonesia.

Evangelio, F.A., F.G, Villamayor Jr., A.G. Dingal, J.C. Ladera, A.C. Medellin, J.

Miranda and G.E. Sajise Jr. 1995. Recent progress in cassava agronomy research in

the Philippines. In: R.H. Howeler (Ed). Cassava Breeding, Agronomy Research and


India. Nov 2-6, 1993. pp.290-305.

Guritno, B. 1989. Tumpangsari pada tanaman ubikayu sebagai usaha peningkatan

penyediaan pangan dan pendapatan petani (Cassava intercropping, a way to increase

farmer income and food need). PT. Jawa Post, Surabaya. 44p.

Howeler, R.H. 1981. Mineral Nutrition and Fertilization of Cassava. Centro Internacional

de Agricultura Tropical. Cali, Colombia. 52p.

Hozyo, Y., M. Megawati and J. Wargiono. 1984. Plant production and the potential

productivity of cassava. Contribution Central Res. Inst. Food Crops. Bogor. 73:1-20.

Moreno, R.A. and R.D. Hart. 1978. Intercropping with cassava in Central America. In:

Proc. Intern. Workshop on Intercropping with Cassava, held in Trivandrum, Kerala,

India. pp. 17-24.

Nayar T.V.R., S. Kabeerathumma, V.P. Potty and C.R. Mohankumar. 1995. Recent

progress in agronomy research in India. In: R.H. Howeler (Ed). Cassava Breeding,

Agronomy Research and Technology Transfer in Asia. Proc. 4th Regional Workshop, held in

Trivandrum, Kerala, India. Nov 2-6, 1993. pp.61-83.

Sittibusaya C, C. Thiraporn, A. Tongglum, U. Cenpukdee, V. Vichukit, S. Jantawat and R.H.

Howeler. 1995. Recent progress in cassava agronomy research in Thailand. In: R.H.

Howeler (Ed.). Cassava Breeding, Agronomy Research and Technology Transfer in Asia.

Proc. 4th Regional Workshop, held in Trivandrum, Kerala, India. Nov 2-6, 1993. pp. 1 10-123.

Suwardjo, H. and N. Sinukaban. 1986. Masalah erosi dan kesuburan tanah di lahan

kering Podsolik merah kuning di Indonesia. Proc. Lokakarya Usahatani Konservasi.

(Erosion and soil fertility problems of Red Yellow Podzolic soils in Indonesia)

Litbangtan-Ditjenbun-PT. Mosanto. Palembang. pp. 1-20.

Wargiono, J. 1988. Agronomic practices in major cassava growing areas of Indonesia.

In: R.H. Howeler and K. Kawano (Eds.). Cassava Breeding and Agronomy Research

in Asia. Proc. 2nd Regional Workshop, held in Rayong, Thailand. Oct 26-28, 1987.

pp. 185-205.

Wargiono, J. 1993. Penampilan clon ubikayu pada pola tanam berbeda (Performance of cassava

clones in different intercropping systems). Sem. BORIF, Bogor.

Wargiono, J., B. Guritno and K. Hendroatmodjo. 1992. Recent progress in cassava

agronomy research in Indonesia. In: R.H. Howeler (Ed.). Cassava Breeding,

Agronomy and Utilization Research in Asia. Proc. 3rd Regional Workshop, held in

Malang, Indonesia. Oct 22-27, 1990. pp. 185-198.

Wargiono, J., B. Guritno, Y. Sugito and Y. Widodo. 1995. Recent progress in cassava

agronomy research in Indonesia. In: R.H. Howeler (Ed.). Cassava Breeding,

Agronomy Research and Technology Transfer in Asia. Proc. 4th Regional Workshop,

held in Trivandrum, Kerala. India. Nov 2-6, 1993. pp. 147-174.

Widjaya, I.P.G., I.P.G. Wigena, W. Hartatik and A. Sofyan. 1990. Efisiensi penggunaan

pupuk di lahan kering (Efficiency of fertilizers on upland soils). Lokakarya Nasional

Efisiensi Penggunaan Pupuk V. Bogor, Indonesia. 28p.

331

RECENT PROGRESS IN CASSAVA AGRONOMY RESEARCH IN THE

PHILIPPINES

Fernando A. Evangeliol and Julieta C. Ladera2

ABSTRACT

During the last three years cassava production in the Philippines did not progress

markedly, neither in area nor in volume. In terms of area, there was only an increase of 14,424

ha or 6.4%, while in terms of volume the increase was 112,177 metric tons or 5.7%. One of the

reasons for this was the unstable price for chips, especially in 1994/95. Up to the present, cassava

cultivation is still concentrated in Mindanao where there are greater opportunities for marketing,

particularly trading of dry chips by the San Miguel Corporation and animal feed millers, as well

as fresh roots for production of starch.

In terms of research, not much data has been generated, since only very few experiments

were conducted. Some experiments were terminated, like the one on cropping systems trials in

Negros Occidental. In Leyte the fifth cropping cycle of the long-term fertility trial under coconut

showed no significant responses to fertilizers, but there were some responses in the sixth year of

consecutive cropping. In the erosion control trial, highest soil losses were observed in plots with

application of inorganic fertilizers (14-14-14), while the lowest soil losses were observed in plots

with vetiver grass barriers or with grass mulch. Root yields were highest with the application of

grass mulch or when Crotalaria juncea was intercropped and mulched at 2 months; yields were

lowest in plots with lemon grass barriers.

The variety x fertilizer trial in Bontoc, southern Leyte, showed a clear varietal response

to fertilizers. The variety with a heavier canopy responded more markedly to fertilizer

applications.

In an intercropping trial in Bohol, even after three cropping cycles, cassava yields were

not significantly affected by interplanting of either soybean, mungbean, cowpea, peanut or pole

sitao (yard-long bean). However, row spacing significantly affected the yields of cassava and

intercrops. In another trial, marked increases in cassava yields were obtained when the plant

densify was increased to 15,000-25,000 plants/ha. On the other hand, no significant differences

were observed when the age of pruning cassava was varied.

INTRODUCTION

The cassava industry in the Philippines is now gaining momentum with the

existence of various market opportunities. Cassava is grown not only for human food,

but also for starch, feed and industrial uses such as alcohol. Aside from the San Miguel

Corporation, which currently exports cassava chips to Europe and uses cassava meal as

an ingredient in animal feed, other firms, like La Tondena, are also working with

cassava as a raw material for production of alcohol. This is due to scarcity of molasses

resulting from low sugarcane production. Moreover, various food products from cassava

are now developed, further increasing the demand for the crop.

1 Director, Philippine Root Crops Research and Training Center (PRCRTC), Baybay, Leyte,

Philippines.

2 Central Visayas Integrated Agric. Research Center (CVIARC), Gabi, Ubay, Bohol,

Philippines.

332

Cassava Area and Production

During the last three years (1993-1996) cassava production in the Philippines did

not increase very much, neither in area nor in volume (Table 1). In terms of area, there

was only an increase of 14,430 ha from 21 1,420 to 225,850 ha, which is an increase of

6.8%. In terms of volume, the increase was 112,177 metric tons or 5.7%. One of the

reasons for the slow growth of cassava production was the unstable price for chips,

especially in the 1994/95 season. Up to the present, cassava cultivation is still

concentrated in Mindanao because of the greater market opportunities, particularly the

presence of chips traders like the San Miguel Corporation, feed millers and starch

processors.

Table 1. Cassava area, production and yield by region in the Philippines during the

last five years (1991-1995).

Region 1991 1992 1993 1994 1995

Cassava area (ha)

Philippines 211,036 204,313 211,420 213,090 225,852

Ilocos 1,807 1,805 2,207 2,210 2,218

Cagayan Valley 354 411 384 350 398

C. Luzon 1,240 1,148 1,160 1,230 1207

S. Tagalog 10,264 10,048 10,418 10,460 10,617

Bicol 30,960 31,188 31,048 28,990 28,417

W. Visayas 9,568 9,548 8,993 8,800 8,661

C. Visayas 20,595 19,387 20,751 20,940 20,136

E. Visayas 25,111 24,009 24,033 24,280 26,679

W. Mindanao 22,643 22,512 22,588 22,820 22,650

N. Mindanao 10,949 12,588 15,349 15,460 13,780

S. Mindanao 3,017 3,134 3,278 3,300 2,610

C. Mindanao 1,636 1,589 1,655 1,670 1,570

CAR" 301 294 312 320 319

ARMM2) 63,913 58,430 60,742 63,740 79,140

CARAGA3' 8,678 8,222 8,502 8,520 7,450

333


Region 1991 1992 1993 1994 1995

Cassava production (t)

Philippines 1,815,700 1,784,897 1,844,377 1,891,780 1,956,574

Ilocos 10,656 10,269 11,771 12,134 12,868

Cagayan Valley 1,317 1,321 1,312 1,565 1,832

C. Luzon 7,776 7,972 7,532 7,890 7,744

S. Tagalog 62,800 64,066 63,515 63,751 65,861

Bicol 249,587 254,930 251,362 240,990 236,227

W. Visayas 50,238 47,857 46,822 45,979 45,000

C. Visayas 160,866 148,747 159,896 160,462 162,287

E. Visayas 96,722 92,849 93,975 94,856 92,678

W. Mindanao 218,422 215,652 220,528 227,391 226,634

N. Mindanao 103,041 1 17,727 156,709 157,086 139,139

S. Mindanao 24,949 25,679 26,547 26,245 23,020

C. Mindanao 10,773 11,066 11,230 12,691 12,864

CAR" 2,836 2,950 2,972 3,008 2,936

ARRM2) 783,734 753,886 758,609 806,135 894,815

CARAGA3' 31,983 29,926 31,597 31,597 32,669

Cassava yield (t/ha)

Philippines

Ilocos

Cagayan Valley

C. Luzon

S. Tagalog

Bicol

W. Visayas

C. Visayas

E. Visayas

W. Mindanao

N. Mindanao

S. Mindanao

C. Mindanao

CAR"

ARMM2)

CARAGA3'

8.60

5.90

3.72

6.27

6.12

8.06

5.25

7.81

3.85

9.65

9.41

8.27

6.58

9.42

12.26

3.69

8.74

5.69

3.21

6.94

6.38

8.17

5.01

7.67

3.87

9.58

9.35

8.19

6.96

10.03

12.90

3.64

8.72

5.33

3.42

6.49

6.10

8.10

5.21

7.70

3.91

9.76

10.21

8.10

6.79

9.53

12.49

3.72

8.88

5.49

4.47

6.41

6.09

8.31

5.22

7.66

3.91

9.96

10.16

7.95

7.60

9.40

12.65

3.71

8.66

5.80

4.60

6.42

6.20

8.31

5.20

8.06

3.47

10.01

10.10

8.82

8.19

9.20

11.31

4.39

"CAR = Cordillera Autonomous Region

2)ARMM = Autonomous Region of Muslim Mindanao

3)CARAGA = Newly created region comprising the provinces of Surigao del Norte,

Surigao del Sur, Agusan del Norte and Agusan del Sur

Source: Bureau of Agricultural Statistics

334

Cropping Systems

The most common cropping system used by farmers is intercropping cassava

with maize. This is practiced by farmers in Bukidnon , Mindanao and Camotes Island

in the Visayas, where cassava is planted in the furrow right after the hilling up of maize.

In this manner, the farmers can save labor and reduce costs in land preparation,

cultivation and even fertilizer application. When the maize is harvested, the stover is

either cut or pulled down to the ground as dried mulch, thus allowing the full exposure

of cassava plants to sunlight. This practice has been proven to be successful and

profitable, and is now being adopted by other cassava farmers, especially if their farms

are flat and in open fields.

Some farmers also grow cassava in rotation with legumes or maize, or plant

casssava under coconut. In large plantations like Matling in Malabang, Lanao, cassava

is rotated with sorghum, which is used for livestock feed.

RESEARCH RESULTS

Recent Experiments in Leyte

1. Long-term fertilizer trial under coconut. A long-term fertility trial under

mature coconut trees spaced at about 8 x 8m, showed that yield differences due to

fertilizer application were not significant in the fifth, but were significant in the sixth

cropping cycle (Table 2). Highest yields were generally obtained from the treatment

with 60 kg N, 90 P205 and 60 K20/ha (F8), while lowest yields were obtained in

treatments without N and K application (F2 and F9), suggesting mainly a deficiency of

these two nutrients (Figure 1). Soil analysis of the NPK check plots in 1996 indicated

an intermediate level of 4.09% organic matter, but a very low level of K (0.07 me/100

g) and P (0.35 ppm Bray-H-extractable P). Thus, significant responses to N, P and K

applications are in accordance with soil analysis results.

2. Variety x fertilizer trial. A variety x fertilizer trial was conducted in Bontoc,

southern Leyte in an area with a slope of 20%, but with double hedgerows of Gliricidia

sepium and vetiver grass. Results show that different varieties had significantly different

responses to fertilizer (Table 3). The cassava variety with the heavier canopy (VC-3)

responded most markedly to fertilizers. However, there was no significant difference

between the levels of fertilizer application.

3. Cultural practicesfor erosion control. Table 4 indicates that during the 6th

cropping cycle of the erosion control trial in Baybay, Leyte, soil loss was highest at 45.0

t/ha in plots with inorganic fertilizer (14-14-14) and lowest in plots with vetiver grass

contour barriers (8.1 t/ha). On the other hand, cassava yields were highest in plots

applied with dried grass mulch (14.5 t/ha) and lowest in plots with vetiver or lemon grass

as contour barriers.

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Table 2. Root yield of cassava, cv. Golden Yellow, grown under coconut trees as

affected by different levels of N, P and K fertilizers during the fifth and

sixth cropping cycles in ViSCA, Baybay, Leyte, Philippines.

Treatment N-P205-K2O

(kg/ha)

1. 0-0-0

2. 0-60-60

3. 30-60-60

4. 60-60-60

5. 90-60-60

6. 60-0-60

7. 60-30-60

8. 60-90-60

9. 60-60-0

10. 60-60-30

11. 60-60-90

12. 90-90-90

CV(%)

F test: Global:

Root y ield (t/ha)

5th year 6th year

1993/94 1994/95

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5.95a 15.20c

5.87a 16.72bc

8.37a 17.27bc

7.95a 18.92abc

8.17a 18.97abc

7.92a 18.72abc

10.17a 23.35a

6.32a 17.00bc

8.60a 20.90ab

8.15a 21.87ab

8.17a 18.10bc

N:

P:

K:

35.60 28.90

NS"*

NS NS

NS NS

NS NS

"NS = not significant

* = significant (P<0.05)

Mean separation: DMRT (0.05)

Table 3. Cassava yield (t/ha) of four varieties grown with and without fertilizers on

20% slope in Bontoe, southern Leyte, Philippines in 1993/94.

Variety

0-0-0

Fertilizer Level

60-60-60 Average

VC-1

VC-2

VC-3

Lakan

52.3a

22.6b

22.6b

29.5b

52.8a

25.6b

32.4a

32.6a

52.5a

24.1c

27.5c

31.0b

Average 31.8b 35.8a

337

3.5c 17.9c

8.4bc 45.0a

5.7c 8.1d

14.5a 10.7d

10.7b 28.5b

Table 4. The effect of various cultural practices on cassava yield and soil loss due

to erosion during the 6th consecutive cropping cycle on 25% slope in

Baybay, Leyte, Philippines. (1993/94: 3,154 mm rainfall)

Root yield Soil loss

Treatments" (t/ha) (t/ha)2)

CT with lemon grass hedgerows

CT with 60-60-60 fertilizer

CT with vetiver grass hedgerows

CT with dried grass mulch

CT with Crotalaria juncea intercrop

"CT= check treatment

2>Dry soil loss during the cropping cycle.

Recent Experiments in Bohol

7. Intercropping. Table 5 shows the yields of cassava and intercrops as

influenced by cassava planting arrangement during three cropping cycles at Bohol

Experiment Station in Ubay, Bohol, Philippines. It was observed that even after three

cropping cycles cassava yields were not significantly affected by interplanting of either

soybean, mungbean, cowpea, peanut or pole sitao (yard-long bean). However, plant

spacing significantly affected the yields of cassava and intercrops. Double-row planting

of cassava (0.81 x 0.71 m in the double row, 2.0 m between double rows) generally

resulted in the highest cassava yields, but a normal square arrangement (1.0 x 1.0 m)

gave the heighest intercrop yields during all three years.

2. Prunning. Cutting of cassava plant tops (pruning) at 30 cm above ground

level before or right after a typhoon damages the plantation, may result in improved root

yields, depending on the time of pruning. Moreover, planting at closer spacing has also

been found to mitigate the damaging effect of typhoons. For that reason, a time of

pruning x plant spacing trial was initiated in Bohol in 1995. Table 6 presents the first

year's result. There were no marked differences in the yield of cassava due to time of

pruning but pruning did reduce yields on average 13-21%; this yield reduction was

greater at wider than at closer spacing. Spacing had a significant effect on cassava yield.

Highest yields were obtained in plots with planting distances of 0.80m x 0.80m or 0.60m

x 0.60m. This implies that higher population densities can result in higher cassava

yields, either with or without pruning.

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339

Table 6. Effect of pruning and planting distance on the yield of cassava at Bohol

Experiment Station, Ubay, Bohol, Philippines in 1995/96.

Planting distance

1

Pruning treatments"

Average

1 x lm

0.80 x 0.80m

0.60 x 0.60m

Average

19.92 14.61 14.58 15.63 16.18

23.67 17.61 21.36 21.26 20.97

23.55 20.64 21.69 21.52 21.85

22.38 17.62 19.21 19.47 19.67

" 1 =no pruning

2- pruning at 5 months after planting (MAP)

3 = pruning at 7 MAP

4 = pruning at 9 MAP

CONCLUSIONS

During the past three years there has only been a slight increase in cassava

production in the Philippines, both in area and in volume. Cultivation of the crop is still

concentrated in Mindanao where there are better market outlets, such as chips traders,

feed millers and starch processors.

In Baybay, Leyte, cassava planted under coconut trees responsed more to K and

N and less to P after six years of continuous cropping. Contour barriers of vetiver grass

and application of dry grass mulch resulted in low levels of soil loss due to erosion,

while cassava root yield was high in plots with application of grass mulch or Crotalaria

juncea as intercrop. A variety with a heavier canopy responded most markedly to

fertilizer application in Bontoc, Leyte.

In intercropping trials in Bohol, cassava yields were not affected by any of the

legume intercrops, but yields were affected by plant spacing. Pruning did not affect

cassava yields, but closer spacing significantly increased yields.

REFERENCES

Bureau of Agricultural Statistics. 1996. Agricultural Statistics for 1995. Mimeographed sheets.

Evangelio, F. A., F. G. Villamayor, Jr., A. G. Dingal, J.C Ladera, A.C. Medellin, J. Miranda

and G.E Sajise Jr. 1995. Recent progress in cassava agronomy research in the Philippines.

In: R.H. Howeler (Ed.). Cassava Breeding, Agronomy Research and Technology Transfer in

Asia. Proc. 4th Regional Workshop, held in Trivandrum, Kerala, India. Nov 2-6, 1993.

pp. 290-305.

340

VARIETAL IMPROVEMENT AND AGRONOMY RESEARCH IN MALAYSIA

S.L. Tan'

ABSTRACT

Over the period 1994-1996, seven batches of seeds and two of meristem tissue cultures

were evaluated and selected. As important as root yield is the trait starch content (or dry matter

content) if a clone is to be accepted as a starch cultivar. At the time of reporting a number of

clones have been identified as having yield levels similar to the high-yielding early cultivar MM

92, while showing dry matter contents equivalent to that of the commercial starch cultivar Black

Twig. Two of these promising clones have also been evaluated positively for processing into oil-

fried crisps, a popular local snack.

Agronomic research included various studies on nutrient inputs and the effects of flooding

on cassava performance when the crop is planted on drained peat. With the early cultivar MM

92, fertilizer inputs may be halved and applied once every alternate cropping without affecting root

yields. While the effect of Ca application was not clear-cut, there was some indication that Ca

applied as a 9 % foliar solution of Ca(NO3)2 or as 1 ,500 kg/ha of CaCO3 to the soil improved root

dry matter content. Solid wastes from starch processing factories may be returned to the soil at

the rate of 1.0-1.5 t/ha as a supplement to chemical fertilizer inputs. MM 92, in contrast to 12-

month Black Twig (critical stage at 3 1/2 months), showed the greatest yield reduction when

flooding occurred at 4-5 months after planting. Four days of continuous flooding resulted in

yields declining as much as 45%.

INTRODUCTION

Malaysia and MARDI (the Malaysian Agricultural Research and Development

Institute) have reached a major cross-road as far as cassava research is concerned. Labor

costs, and indeed availability of agricultural labor, have become a major constraint to

small-scale cultivation of cassava. Technology packages for mechanized production have

been formulated by MARDI, but require a scale of production of at least 400 ha of

cultivated area (Sukra et al., 1992). On the other hand, to keep a starch factory with a

minimal daily capacity of processing 150 t fresh roots (Mat Isa, A., Food Technology

Research Centre, MARDI, Serdang,pers. comm.) well-supplied with roots would require

a cultivated area of at least 1,650 ha. This assumes fresh root yields of 25 t/ha, 275

working days in a year, and that the factory operates a single 8-hour shift per day.

However, land of less than 14% slope (to allow for mechanization without accompanying

risks of soil erosion) of the required area in one contiguous piece is no longer so easily

available for cassava cultivation in Peninsular Malaysia, where the demand for starch is

strong.

Sustained research on cassava, particularly in the fields of breeding/selection and

agronomy, has been going on for more than two decades in MARDI, and many practical

and cost-effective technologies have been generated. Adoption of those technologies by

the end-user, however, has been less than enthusiastic or satisfactory, largely due to the

1 Sweet potato and cassava breeder, Food and Industrial Crops Research Centre, MARDI,

P.O. Box 12301, 50774 Kuala Lumpur, Malaysia.

341

constraint of land availability.

For these reasons, in Malaysia.s Seventh Development Plan, covering the period

1996-2000, funding for cassava research has been discontinued. Starch, on the other

hand, is anticipated to have a growing demand, especially in the widely varied processed

food industries (Tan, 1996). Hence, research emphasis has shifted to sweet potato as a

possible alternative starch source.

MARDI is also on the treshold of embracing a corporate image, which brings

with it an increasingly important role in income generation for the institute through such

activities as consultancy services, contract research, patents and copyrights. Having built

up strong expertise in cassava production technology, prospects are sound in attracting

consultancy services. There has been encouraging interest from the private sector to

invest in cassava production in the east Malaysian states of Sabah and Sarawak, as well

as in other Southeast Asian countries where labor availability is still secured. Thus,

while active cassava research in MARDI may wind down in the coming years, the

promotion of cassava technologies will remain a significant role of the institute.

The cassava breeding and selection program has CIAT to thank for keeping it

alive for a few more years through the mechanism of the small contract agreement.

These modest funds will ensure that the evaluation and selection of short-listed clones

may be completed satisfactorily.

VARIETAL IMPROVEMENT 1994-1996

Anticipating the gradual closure of the cassava research program, only two seed

batches were introduced since the last Asian Cassava Research Workshop. In 1994,

1,141 seeds, labeled batch (CIAT 13 (TH), were sent from the CIAT-Thai program,

while 1,040 seeds (CIAT 14) came from CIAT Headquarters in Cali. The germination

rate was quite different for the two batches: 59% for CIAT 13 (TH) resulting in 673

seedlings, and only 7.8% for CIAT 14, giving 81 seedlings.

Over the period 1994-1996, evaluation and selection following the usual stages

of Seedling, Single-row, Preliminary, Advanced and Regional Yield Trials involved

materials introduced from 1989-1994 (Table 1).

Past experience shows that mere high root yield (as in cv. Perintis), even with

an early harvestable characteristic (as in cv. MM 92), is insufficient to attract wide use

of the clones by farmers, especially those supplying the starch processors. This is due

to the existence of a price discounting system based on a minimal root starch content of

28% . In an effort to ensure greater acceptability of the new clones, intermediate (i.e. as

high as the local cultivar Black Twig) to high root starch content has become a significant

selection criterion. Latest harvest data from the yield trials are given in Tables 2 to 5.

In all the trials, three control cultivars were used, namely Black Twig, Perintis and MM

92.

342

Table 1. Stage of evaluation and selection of CIAT germplasm over the period

1994-1996.

Seedstock Stage of evaluation Year No. clones

CIAT8 Regional Trials 1993-1995 7

CIAT7 +CIAT9(TH)" Advanced Yield Trials 1993-1995 16

CIAT 10 Advanced Yield Trial

Regional Trial

1994-1995

1995-1997

20

7

CIAT 1 1 Preliminary Yield Trial

Advanced Yield Trial

1994-1995

1995-1996

20

12

CIAT 12 Single-row Trial

Preliminary Yield Trial

1994-1995

1995-1996

25

5

CIAT 13 (TH)" Seedling Evaluation

Single-row Trial


1994-1995

1995-1996

1996-1997

673

37

14

CIAT 14 Seedling Evaluation

Single-row Trial

1994-1995

1995-1996

81

16

Meristems 1990 Advanced Yield Trial

Regional Trial

1994-1995

1995-1997

10

4

Meristems 1991 Single-row Trial


Advanced Yield Trial

1994-1995

1995-1996

1996-1997

7

7

7

TH = introduced from the Thai-CIAT program

Although in a Regional Trial shown in Table 2, SM814-18 produced root yields

at 6 and 12 months equivalent to those of Perintis and MM 92, its dry matter content was

unfortunately as low as these two clones, so the clone did not merit final selection. In

the recently harvested Regional Trial (Table 3), MKUC28-77-3 and Rayong 60 showed

promise at 6 months: their root yields were not significantly different from the controls,

while dry matter contents were similar to that of Black Twig. However, at 12 months,

the best yield of 41.2 t/ha was obtained with CM6149-30 (although not significantly

different from the three controls). Taking root dry matter content into consideration, the

highest dry root yield was also recorded for the same clone. CM6149-30 had a dry

343

matter content similar to that of Black Twig, and therefore significantly higher than those

of Perintis and MM 92. Rayong 60, together with CM6149-23, CM6149-54 and

CM6885-75, had dry root yields (ranging from 10.7 to 11.3 t/ha) similar to the controls

because of their intermediate to high dry matter contents. CM6885-75 had a root dry

matter content of 43.0%.

Table 2. Mean data from a Regional Trial on "CI AT 8" seed batch over two seasons

at Pontian peat station, Johore, Malaysia.

Clone

6-month data 12-month data

Root Harvest RDMC" Root Harvest RDMC"

yield index (%) yield index (%)

(t/ha) (t/ha)

OMR32-06-21 20.3 0.47 34.3 33.6 0.60 34.0

OMR32-06-25 20.2 0.45 30.3 29.1 0.48 30.6

OMR32-06-46 27.8 0.60 29.9 39.8 0.63 26.5

OMR32-06-64 21.6 0.50 31.5 35.2 0.58 37.1

OMR32-30-11 20.0 0.55 32.5 33.7 0.62 37.0

OMR32-30-37 23.2 0.48 30.3 30.2 0.52 36.0

SM814-18 32.6 0.60 27.8 52.7 0.66 26.0

Black Twig 20.4 0.44 27.6 34.0 0.50 29.5

Perintis 29.7 0.58 25.8 53.5 0.65 26.0

MM92 34.7 0.65 25.1 51.4 0.63 19.9

LSD(P = 0.05) 5.4 0.06 4.5 5.6 0.03 4.4

"RDMC = Root dry matter content

In the Advanced Yield Trial, testing clones selected from CIAT 7 and CIAT 9

(TH), the clone SM967-1 showed promise in terms of dry matter content (higher than

that of Black Twig), while having root yields equivalent to that of MM 92 at 6 and 12

months (Table 4). Harvest data from the other Advanced Yield Trial (on CIAT 1 1

clones) showed SM1565-7, SM1562-19 and SM1565-57 to be desirable in terms of dry

matter content, with reasonable root yields at six months, while the first two clones as

well as SM 1794-23 and CM7719-7 were promising in terms of starch content and root

yields at 12 months (Table 5).

344

Table 3. Regional Trial on clones selected from "Meristems 1990" and "CIAT 10"

seed batch (6-and 12-month data) at Pontian peat station, Johore,

Malaysia.

Clone




(t/ha) (t/ha)

Rayong 3 10.6 0.74 38.3 18.2 0.77 38.1

Rayong 60 19.3 0.66 39.3 28.4 0.69 39.1

CMR28-67-76 17.3 0.66 38.8 17.9 0.64 40.3

MKUC28-77-3 18.1 0.66 43.6 27.0 0.68 35.9

CM6 149-23 14.3 0.66 40.5 31.4 0.64 35.7

CM6149-30 22.1 0.63 38.0 41.2 0.67 39.3

CM6 149-54 16.1 0.60 38.0 29.8 0.67 37.4

CM6 149-55 12.6 0.61 40.8 13.6 0.63 41.5

CM6885-75 16.6 0.64 39.8 24.9 0.68 43.0

CM7752-4 11.8 0.60 35.7 18.6 0.63 40.5

CM8061-2 11.8 0.60 40.3 19.2 0.73 37.8

Black Twig 21.7 0.60 41.9 37.1 0.65 39.8

Perintis 20.2 0.69 32.3 39.5 0.80 27.5

MM92 24.4 0.78 28.5 29.8 0.74 26.9

LSD(P=0.05) 9.7 0.10 5.0 13.1 0.08 5.7

)RDMC = Root dry matter content

345

Table 4. Advanced Yield Trial of selected clones from "CIAT 7" and "CIAT 9 (TH)"

seed batches (6-and 12-month data) at Pontian peat station, Johore,

Malaysia.

Clone




(t/ha) (t/ha)

OMR33-15-7 18.3 0.71 17.1 23.6 0.65 32.2

OMR33-15-21 18.3 0.60 25.9 30.3 0.59 33.6

OMR33-06-21 12.4 0.50 30.4 18.9 0.38 40.9

OMR33-63-4 16.1 0.68 35.7 24.3 0.62 36.0

OMR33-63-30 16.5 0.65 30.8 28.1 0.58 36.3

OMR33-63-9 14.3 0.68 30.3 22.7 0.59 39.6

SM836-10 20.7 0.58 26.0 32.8 0.60 31.7

SM%7-1 22.4 0.66 29.3 31.1 0.63 36.7

SM987-13 20.7 0.62 23.7 36.5 0.60 27.4

Adira 4 15.4 0.62 25.5 31.1 0.60 32.1

Black Twig 24.2 0.68 23.8 34.3 0.64 33.4

Perintis 19.3 0.69 22.8 31.2 0.72 27.1

MM 92 23.1 0.76 21.4 33.3 0.68 19.7

LSD(P=0.05) 5.0 0.08 8.6 8.1 0.06 4.7

l)RDMC=Root dry matter content

346

Table 5. Advanced Yield Trial on selected clones from "CIAT 11" seed batch

(6-and 12-month data) at Pontian peat station, Johore, Malaysia.

Clone




(t/ha) (t/ha)

CM6658(C)-2 9.8 0.20 25.3 32.2 0.42 38.2

SM 1583-2 16.1 0.37 31.1 36.4 0.52 41.5

CM6098-45 11.8 0.21 29.8 25.6 0.35 39.5

SM 1565-7 24.3 0.45 29.6 41.7 0.57 40.3

SMI 565-57 20.1 0.45 36.0 28.3 0.51 41.1

CM8223-29 9.7 0.24 29.5 22.6 0.31 40.4

CM8223-30 16.8 0.33 27.1 35.0 0.48 40.7

CM6517-9 11.8 0.30 29.6 30.6 0.44 40.0

SM1562-19 23.6 0.41 31.6 36.8 0.55 37.5

SMI 794-23 14.9 0.39 33.7 41.0 0.56 40.3

CM7719-7 12.1 0.25 32.9 43.6 0.47 37.2

CM7719-23 11.2 0.24 31.3 35.3 0.51 38.8

Black Twig 11.4 0.16 27.1 38.1 0.42 36.2

Perintis 23.1 0.43 25.8 50.8 0.55 33.4

MM92 29.6 0.48 25.1 45.7 0.56 32.1

LSD(P= 0.05) 5.6 0.12 6.5 9.7 0.10 6.6

"RDMC = Root dry matter content

Recent trends show a growing demand for edible cassava types for processing into

oil-fried crisps, a popular snack locally known as kerepek. This cottage industry is

gaining ground, especially in Johore with its close proximity to the Singapore market.

To capitalize on this demand, root samples from the three promising clones at six months

(from CIAT 1 1), which also have low root cyanide contents (< 60 ^g HCN/g fresh root),

were sent to a kerepek processor to test their acceptability for this type of utilization.

The feedback has been enlightening: SM1562-19 was considered to be superior to the

local cultivars currently used, SM 1565-57 was acceptable as a substitute, while SM1565-

7 was rejected because of its hard texture when so processed. Such information coming

from the Advanced Yield Trial will be very beneficial in making the final selections for

the Regional Trials.

The above results show that it is becoming increasingly difficult to raise root

yields above those of the released cultivars. However, there is still room for

347

improvement of the dry matter content (i.e. the starch content) at this yield level.

AGRONOMY RESEARCH 1994-1996

Agronomy research on cassava terminated in 1995 with the retirement of the

agronomist, Mr. Chan Seak Khen, and the resignation of his replacement. Although the

breeder shouldered the responsibility of the ongoing research trials for a short time,

increasing work pressure from sweetpotato research has caused her to abandon further

efforts after completion of those trials. What follows is a summary of the findings of

final agronomy research on cassava conducted by MARDI.

Reduction of fertilizer use with an early clone

Using the six-month cultivar MM 92, this trial was conducted on drained peat

over six cropping cycles, beginning in 1991. Fertilizer inputs for cassava on peat have

been high (200 kg N, 30 P2O5 and 160 K2O/ha) in the past when the 12-month Black

Twig cultivar was used (Tan and Chan, 1994). The nine treatments included a

combination of fertilizer rates and frequency of application as follows:

Application rate over 6 crops" Percent of

Treatment

t

Control 1

1st 2nd 3rd 4th 5th 6th

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" each crop of 6 months duration

1: full rate of fertilizers (200:30:160)

XA: half rate of fertilizers (100: 15:80)

0: no fertilizers

348

Results show that when MM 92 was grown, the fertilizer rate could be reduced

by half, and this half rate (100: 15:80) could be applied to every alternate crop instead of

every season without affecting either fresh or dry root yield (Figures 1A and IB). Root

dry matter content was unaffected by any of the fertilizer treatments. The results of this

trial have been published (Tan, 1995).

Effect of waterlogging on cassava performance

These series of experiments conducted in fibre-glass lysimeters filled with peat

soil, started in 1989 using the cultivar Black Twig (harvested at 9 months); in 1992 the

test variety was changed to cultivar MM 92 (harvested at 6 months). The objective of

the experiments was to determine the critical stage of plant growth when flooding had the

most detrimental effects, as well as the effect of flooding duration at this critical stage.

For Black Twig, the critical stage was at Vh months after planting, at the stage

of storage root initiation, when the subsequent root yield could be reduced by 80%.

Figure 2 shows that flooding at this stage, from 1 to 4 days, did not bring about a

significant root yield reduction (although a 25% reduction was observed after 4 days'

flooding). Figure 3 shows that for MM 92 yield reductions up to 80% occurred when

flooding was imposed at 4-5 months. MM 92 showed significant yield declines of 25%

and 45% after flooding for 4 days at Vh months and at 5 months, respectively.

349

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Figure 1. Effect of varying levels andfrequencies offertilizer application on the

cumulative (over six 6-month crops) fresh (A) and dry (B) root yields

of cassava, cv. MM 92, grown at Pontian peat station, Johore, Malaysia.

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352

Effect of Ca on performance of cv. Perintis

Results from an earlier trial suggested a possible role of Ca in enhancing root

yield to levels in excess of 100 t/ha, as well as starch content in the cultivar Perintis

(Chan and Tan, 1994). The experiment, carried out over two consecutive seasons, tested

different sources of Ca (applied in different ways) as well as varying rates on Perintis

planted at the peat station in Pontian, Johore. Nine treatments were tested against two

controls:

FN1 Foliar spray of 3% Ca(NO3)2 solution at 2 and 3 months



SGI Soil application of 312.5 kg gypsum/ha at 3 weeks by banding

(equivalent to 100 kg Ca)

SG2 Soil application of 625 kg gypsum/ha at 3 weeks by banding


SG3 Soil application of 937.5 kg gypsum/ha at 3 weeks by banding


SL1 Soil application 2 weeks prior to planting by broadcasting of 500 kg

CaCOj/ha

SL2 Soil application 2 weeks prior to planting by broadcasting of 1,000 kg

CaCO3/ha

SL3 Soil application 2 weeks prior to planting by broadcasting of 1,500 kg

CaCOj/ha

000 Control 1: no Ca application

00N Control 2: similar to Treatment FN3 but with 3.8% NH4NO3 solution

(equivalent in terms of N to 9% Ca(NO3)2

While results were far from conclusive, there was some indication that root dry

matter content was improved by 12.6-22.0% (over the two controls) when Ca was

applied as a foliar spray at 2 and 3 months using a 9% Ca(NO3)2 solution, or soil

application of 1,500 kg CaCO3/ha two weeks before planting (Table 6). Fresh root

yields were unaffected by any of the treatments, although the foliar spray of 9%

Ca(NO3)2 reduced yield by as much as 12.6% over Control 2.

Alternate sources of nutrients for cassava production

Solid wastes from starch processing factories have traditionally been sold as a

cheap feedstuff to livestock farmers and feedmillers. However, there is less and less

demand for these wastes because of their poor nutrient content. Such wastes constitute

a potential environmental pollution hazard. A logical solution would be to re-use these

wastes as a nutrient input to supplement chemical fertilizers.

353

Varying rates of dry starch factory wastes (0, 0.5, 1.0, 1.5 t/ha) in combination

with chemical fertilizers (50-30-40 and 100-30-80 kg N-P2O5-K20/ha of NPK mixture)

were evaluated over two seasons using the cultivar MM 92 as the test variety on peat.

Results show no significant effects on fresh root yield when starch factory wastes

were used in combination with chemical fertilizers (Table 7). Nevertheless, using the

higher rate of chemical fertilizers (Control) produced a 15% yield improvement over the

lower rate. However, using from 1.0-1.5 t/ha of starch factory wastes in combination

with the lower and higher fertilizer rates, respectively, was able to maintain starch

content as high as in the Control (Table 7).

Table 6. Effects of source and rate of Ca on fresh root yield and root dry matter

content of cultivar Perintis planted at Pontian peat station, Johore,

Malaysia.

Treatment Fresh root Dry matter

yield content

Source Rate (t/ha) (%)

Ca(NO3)2 3% foliar spray 55.1 28.1



gypsum 312.5 kg/ha to soil 47.1 28.5

gypsum 625 kg/ha to soil 47.4 28.7

gypsum 937.5 kg/ha to soil 51.2 29.0

CaCO3 500 kg/ha to soil 53.3 29.2



Control 1 NoCa 51.4 27.3

Control 2 N equiv. to 9% Ca(NO3)2 52.4 27.8

Significance level NS" NS

"NS = not significant

354

Table 7. Effect of using starch factory wastes in combination with chemical

fertilizers on the yield and starch content of cassava (cv. MM 92) grown at

Pontian peat station, Johore, Malaysia.

Fresh root Starch

Treatment" yield content

(t/ha) (%)

M1W0 24.0a2) 24.5b2)

M1W1 26.1a 24.1b

M1W2 26.7a 25.3ab

M1W3 25.2a 23.9b

M2W0 (Control) 27.6a 26.4a

M2W1 26.3a 24.2b

M2W2 27.4a 23.8b

M2W3 25.6a 25.4ab

Ml = 50-30-40 kg N-P205-K20/ha of NPK mixture

M2 = 100-30-80 kg N-P205-K20/ha 0f NPK mixture

W0 = 0 t wastes/ha

Wl = 0.5 t wastes/ha

W2 = 1 .0 t wastes/ha

W3 = 1.5 t wastes/ha

Values in the same column bearing the same letter are not significantly different from

one another according to Duncan's new muliple range test (P=0.05)

REFERENCES

Chan, S.K. and S.L. Tan. 1994. Effect of spacing and fertilizer rate on the performance of

cassava, cultivar Perintis, planted on two peat soils. MARDI Res. J. 22(l):43-54.

Sukra, A.B., S.L. Tan, S.K. Chan and H. Noor Auni. 1992. Pengeluaran ubi kayu secara

berjentera di tanah mineral (Mechanized production of cassava on mineral soils). Paper

presented at the Seminar Expo Tek 92, Serdang, Selangor, Malaysia.Nov 26, 1992. MARDI,

Serdang, Malaysia. 19 p.

Tan, S.L. 1995. Reduction of fertilizer use by planting an early variety of cassava (Manihot

esculenta Crantz). MARDI Res. J. 23(2): 149-159.

Tan, S.L. and S.K. Chan. 1994. Production technology for cassava on peat. In: S.L. Tan et al.,

(Eds.). Proc. National Seminar on Tuber Crop Production and Utilization, held in Kuantan,

Malaysia. Sept 5-7, 1994. MARDI, Univ. Pertanian Malysia, and Malays. Soc. Hort. Sci.

pp. 144-162.

Tan, S.L. 1996. Sweet potato or cassava for starch production on peat? Poster presented at the

10th International Peat Congress. May 27-June 2, 1996. Bremen, Germany.

355

CASSAVA AGRONOMY RESEARCH IN ASIA - AN OVERVIEW 1993-1996

Reinhardt H. Howeler1

ABSTRACT

During the past three years (1993-1996), cassava agronomy research, conducted by

national programs in collaboration with CIAT and with financial support from the Nippon

Foundation in Japan, continued as before but at a slightly lower level of activity. Major emphasis

remained on soil fertility maintenance and erosion control with the objective of enhancing the

sustainability of cassava production in Asia.

Long-term fertility trials have been conducted in 14 locations in four countries. Some

of these trials are now in the 8th or 9th cycle of continuous cassava production. During the latest

crop cycle there was a significant response to N in ten sites, to P in six sites and to K in eleven

sites, indicating the importance of adequate fertilization of cassava with K and N and a lesser need

for P. Especially the response to K increased with successive cassava cropping cycles.

Various types of erosion control trials were continued in 13 sites in five countries.

Research in Thailand indicate that time of planting has a strong influence on erosion, with greatest

soil lasses occurring when cassava is planted in the beginning of the rainy season. For cassava

monoculture the planting on contour ridges, at closer spacing and with adequate fertilization

increased yields and reduced erosion losses. Among various intercropping systems the

interplanting of peanuts is generally most effective in reducing erosion, while also providing a

good additional income. Intercropping with pumpkin or squash was also quite effective, but

watermelons, cucumbers or muskmelon were more difficult to establish. Among various contour

barriers tested, the most suitable were hedgerows of Flemingia congesta and Gliricidia sepium in

Malang, E. Java, Gliricidia and Leucaena leucocephala in South Vietnam, Thephrosia candida

in North Vietnam, and vetiver grass in Nanning, China, and in Leyte, Philippines; application of

grass mulch was even more effective at the latter location. The efficiency of hedgerows of many

other grass species are presently being investigated in Thailand.

Maintaining soil fertility with no or little chemical fertilizers is being investigated in South

Vietnam, Indonesia and Thailand. A crop rotation of cassava with peanut/pigeon pea was found

to be effective in northeastern Thailand. Green manuring with Crotalaria juncea or Canavalia

ensiformis before planting cassava (cassava harvested after 18 months for a 2-year cycle), or

interplanting these same two species and cutting and mulching the legumes at 2 MAP for a 12-

month cassava crop, were found to be most effective in maintaining high yields when only small

amounts of fertilizers were applied. A similar intercropping/mulching treatment with Tephrosia

Candida was also effective in South Vietnam, although intercropping and mulching with cowpea

was even more effective.

Weed control trials have been conducted in Thailand and are being initiated in South

Vietnam. The preemergence herbicide Metolachlor seems effective in both locations and can also

be used when cassava is intercropped with mungbean or peanut. The frequency and cost of

weeding was markedly reduced when cassava was planted at the end rather than the beginning of

the rainy season in Thailand. More efficient methods of weed control, both chemical and

mechanical, need to be further investigated as labor for hand weeding is becoming more and more

expensive.

INTRODUCTION

Cassava agronomy research during the past three years (1993-1996), conducted

by cassava researchers in national programs in collaboration with CIAT, and with

CIAT Asian Cassava Program, Dept. of Agriculture, Chatuchak, Bangkok, Thailand.

356

financial support from the Nippon Foundation in Tokyo, Japan, has continued as before,

albeit at a lower level of activity. This was due to a shift in emphasis from on-station

research to farmer participatory research (FPR). This has reduced the budget available

for basic and strategic research.

As before, the cassava agronomy research has emphasized the maintenance of soil

fertility through biological means or through the application of chemical fertilizers, and

the control of soil erosion through appropriate soil/crop management practices. A limited

amount of research continued on other cultural practices such as plant spacing and weed

control .

SOIL FERTILITY MAINTENANCE

While cassava grows better than most other crops on acid and low fertility soils,

the crop is much more productive on medium or highly fertile soils. When grown in

soils with a limited availability of plant nutrients, cassava plants grow only slowly,

remain short and weak, but are quite effective in translocating carbohydrates from the

shoots to the roots. This results in a rather low yield in spite of a high harvest index

(HI). When grown in a fertile soil or when plant nutrients are added in the form of

manures or chemical fertilizer, the greater absorption of essential nutrients results in

faster growth, more and bigger leaves, longer leaf life, thicker stems and more and

thicker roots. However, if nutrient supply is excessive, especially that of nitrogen (N),

some cassava varieties grow too tall and produce too many leaves resulting in a low HI

and a reduced root yield. Moreover, the excessive supply of phosphorus (P) or

potassium (K) can lead to the reduced uptake of Fe or Zn and Ca or Mg, respectively.

Thus, the maintenance of a balanced nutrient supply is essential for obtaining high yields;

the application of excessive amounts of some nutrient(s) only increases production costs

while it may actually decrease yields. Maintaining adequate soil fertility through

application of manures or the judicious use of chemical fertilizers is not only important

for the supply of nutrients, but also for maintaining optimum soil physical conditions

through the return of organic matter to the soil. This in turn improves the soil's water

holding capacity, nutrient retention capacity and stimulates the soil's micro-flora. When

cassava (or other crops) are grown continuously without manure or fertilizer application,

the soil's nutrient supply as well as its physical properties deteriorate, resulting in

decreased productivity.

1. Fertility Maintenance through Fertilizer Application

Long-term NPK trials continued in 14 sites in four countries. Results of most

these trials were already presented in previous papers in this Workshop (Zhang Weite et

al.; Tongglum et al.; Nguyen Huu Hy et al.; Wargiono et al.; and Evangelio and

Ladera, 1997). Figure 1, showing the cassava response to various levels of application

of N, P and K as well as to that of "burned soil" during the 3rd cropping cycle in

357

CATAS, China, is a good example of this type of trials. In this case there was a

significant and a highly significant response to N for SCI 24 and SC205, respectively;

there was no significant response to P and only a highly significant response to K in

SC205. Similar to results obtained in Nanning (Zhang et al., 1997), variety SC205 was

more responsive to high applications of N, P and K than SC201 or SC124. Due to the

high level of available P is the soil in CATAS (17-20 ppm Bray-2 available P) there was

no response to P application in that site. The combined application of N, P and K

increased yields from 7-8 t/ha to about 26 t/ha. Application of "burned soil" in the

presence of low levels of application of N-P-K, had no effect on yield. The application

of 100 kg N, 25 P205 and 100 K20/ha can probably maintain soil fertility and high yields

of cassava. Figure IB also shows that high applications of N tend to suppress, while

high applications of K tend to increase the starch content of roots. Thus, excessive

application of N can lead to both reduced yields and starch contents.

Figure 2 shows the change in response to the annual application of N, P, and K

during seven consecutive cropping cycles in Nanning, Guangxi, China. With an

intermediate application of 100 kg N, 50 P205 and 100 K20/ha high yields of 20-25 t/ha

could be maintained over the years. However, without N yields decreased from about

20 t/ha in the first year to 10-14 t/ha in subsequent years. The relative yield, i.e. the

yield without the nutrient divided by the highest yield with the nutrient, decreased over

the years, especially for N and K, indicating an increasing response to those two nutrients

over time. The significant response to K and the lack of response to P (in most years)

is reflected by the relatively low K and high P status of the soil (bottom Figure 2).

Without K application the soil K level generally remained below the critical level, while

without P application the soil P content decreased but still remained above the critical

level. The highly significant response to N, in spite of a medium level of soil organic

matter (OM) of 2-3% is probably due to the low pH (4.5) and high Al content (2-3

me/lOOg) of the soil, which tend to reduce the rate of N mineralization.

Table 1 shows the significance of response to N, P and K during the last year

of several cropping cycles in 14 locations in four countries in Asia. The data shows that

there was a statistically significant response to N in ten, to P in six and to K in eleven

locations, indicating the more frequent response to applications of K and N than to the

application of P. This is due to the relatively large removal of K and N in the root

harvest in comparison with that of P, and the presence of a highly effective mycorrhizal

population in most soils, which facilitates the uptake of P by cassava, even from very

low-P soils.

The relationship between relative yield and the N, P or K concentration in

youngest fully-expanded leaf (YFEL) blades at 4-5 months after planting (MAP) is shown

358

for data of four NPK trials in Figure 3. There was a good relationship between relative

yield and the N and K concentration of the leaves, allowing the estimation of a critical

concentration (corresponding to 95% of maximum yield) of 5.7% N and 1.9% K. These

critical levels are higher than those reported earlier (4.6% N and 1.7% K) (Howeler,

1995B), but are within the "sufficiency" range reported elsewhere for these elements

(Howeler, 1996). Figure 3 shows no clear relationship between P response and the P

concentration in YFEL-blades, probably due to a lack of serious P deficiency in the four

locations for which data are available.

Table 1. Response of cassava to annual application of N, P or K after several years

of continuous cropping in various locations in Asia.

Response" to

Country-locaition Years of cropping N P K

China -Guangzhou 4** ** **

-Nanning 7**

NS*

-CATAS 4** * *

Indonesia -Umas Jaya 8 NS NS NS

-Malang 7**

NS*

-Lampung 4**

NS**

-Yogyakarta 4 NS NS NS

Philippines -Leyte 6 NS NS NS

-Bohol 4**

NS**

Vietnam -Bac Thai 6**

NS**

-Hung Loc(wet season) 6 NS** *

-Hung Loc(dry season) 1* * *

-Thu Duc 1** ** **

-Traco 1** * *

NS

*

no significant response,

significant response(P<0.05).

highly significant response(P<0.01).

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Figure 2. Effect of annual applications ofN, PandKon cassava root yield, relative yield (yield

without the nutrient over the highest yield with the nutrient) and the exchangeable Kand

available P (Bray 2) content ofthe soil during eight years ofcontinuous cropping in the

Guangxi Subtrop. Research Institute, Nanning, Guangxi, China.

361

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Figure 3. The relation between the relative yield of cassava, i.e. the yield without the nutrient as

a percent of the highest yield with the nutrient, and the concentration of N, P and K

in the youngest fully-expanded leaf (YFEL)-blades at 3-4 months after planting of

various cultivars planted in four fertility trials in China and Vietnam.

362

Figure 4 shows the relationship between relative cassava yield and the organic

matter, available P and exchangeable K contents in the soil, obtained from yield data and

soil analyses results of ten long-term NPK trials conducted in Asia between 1993 and

1996. Critical levels of 3.2% OM, 7 ppm P (Bray-2) and 0.14 me K/100 g (55 ppm K)

were estimated from these data. These are slightly higher than those estimated from

earlier data from almost the same sites, i.e. 4.5 ppm P and 0.12 me K/100 g (Howeler,

1995A), but fall within the "medium" range reported elsewhere for these soil parameters

(Howeler, 1995B; and Howeler, 1996). These "critical" levels serve only as a general

guide in the interpretation of soil and plant tissue analyses to enable the diagnosis of a

likely nutrient deficiency or toxicity, and to estimate the need for application of a

particular nutrient.

Fertility Maintenance through Green Manuring

Research on soil fertility maintenance or improvement through green manuring,

intercropping or alley cropping has been conducted in Vietnam, Indonesia and Thailand.

In Vietnam the experiment was conducted on a highly-fertile red Latosol (probably

classified as Eutrustox) in Hung Loc Research Center and not much beneficial effect of

green manuring would be expected. Table 2 shows that there was no significant effect

of treatments in the first year, but that some treatments started to improve yields after 3-4

years of continuous cropping. Intercropping and mulching at 2-3 months after planting

(MAP) of cowpea or Canavalia ensiformis increased yields, probably by increasing the

soil moisture conditions during the dry season, or by the slight increase in OM and K

contents of the soil. The beneficial effect of alley cropping was less pronounced, but also

increased over time, especially the alley cropping with Tephrosia candida. Alley

cropping with Gliricidia sepium, Leucaena leucocephala or Flemingia congesta also

significantly increased cassava yields in a low-N soil of Jatikerto Experiment Station in

Malang, Indonesia, after several years of continuous cropping (Wargiono et al., 1995;

Wargionoef a/., 1997)

In Thailand three green manure species, i.e. Crotalaria juncea, Canavalia

ensiformis and pigeon pea, were either intercropped and cut at 2 MAP, interplanted at

7 MAP and cut and mulched before the following planting, or were used as green

manures and pulled up and mulched before planting cassava; in the latter case, cassava

was harvested after 18 months for a two-year cropping cycle. Table 3 shows that in the

sandy clay soil of Rayong Field Crops Research Center the intercropping and mulching

of all green manures increased yields, with Canavalia ensiformis being most effective.

Interplanting at 7 MAP had no beneficial effect on cassava yields, but may benefit the

next crop; the interplanted Crotalaria juncea competed strongly with cassava for soil

moisture during the dry season, resulting in low cassava yields. Green manuring with

Crotalaria or Canavalia markedly increased the yield of 18-months old cassava, more

than doubling that of cassava harvested at 12 MAP. This may be a promising system for

363

the soil and climatic conditions of Thailand. Table 3 also shows that mulching

Crotalariajuncea generally supplied more nutrients than either Canavalia ensiformis or

pigeon pea.

EROSION CONTROL

1. Effect of Crops on Soil Erosion

A comparative study on the effect of various crops on soil erosion and on nutrient

uptake and removal, conducted since 1989 in Sri Racha, Thailand (Putthacharoen, 1993;

Howeler, 1995A), was continued for a second cycle of 27 months between 1991 and

1993. Seven crops were grown in adjacent plots on 7% slope and soil losses due to

erosion were measured at monthly intervals. Figure 5 shows the accumulative erosion

losses during the second cycle. Similar to the first cycle, cassava grown for root

production (spaced at 1.0x1.0 m) resulted in the highest level of erosion, followed by

cassava grown for forage production (spaced at 0.5x0.5 m). Soil loss for cassava root

production was about 130 t/ha in the first crop and about 40 t/ha in the second crop. The

closer spacing of cassava plants used for forage production resulted in considerably less

erosion due to a more rapid canopy closure. Sugarcane also produced high levels of

erosion during the first year after planting, but almost no erosion during the following

ratoon crop. The short-cycle crops of maize, sorghum, peanut and mungbean produced

much lower levels of erosion, ranging from 35 to 55 t/ha in two years (three crops).

Pineapple caused the least amount of erosion since it was not replanted but left as a

ratoon crop during the second cycle. Table 4 shows that cassava yields were low in the

first cycle, but rather normal in the second. Soil losses due to erosion, however, were

very high for cassava in both cycles, about two to six times higher than those of other

crops grown during the same four year period. Thus, under the soil and climatic

conditions of Thailand is seems that cassava indeed causes a lot more erosion than other

crops.

In a similar comparative study conducted on 5% slope in Tamanbogo, Lampung,

Indonesia, cassava again caused higher levels of erosion than any of the other food crops,

but the differences were much smaller than in Thailand, partially because the soils in

Tamanbogo are less erodible than in Sri Racha, Thailand, and partially because the longer

wet season in Tamanbogo allowed the planting of two short-cycle food crops per year,

versus usually only one crop in Thailand. Similar to data presented by Wargiono et al.,

(1997), Table 5 shows that erosion in cassava was considerably higher than in other

crops when no fertilizers were applied, but only slightly higher than other crops when

each crop was adequately fertilized. The consecutive planting of two peanut crops in one

year produced the highest net income and lowest levels of erosion, while cassava grown

in monoculture produced a low income and serious erosion. For that and other reasons,

most farmers in Indonesia plant cassava intercropped with other food crops, which

generally increases income and reduces erosion.

364

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Figure 4. The relation between the relative yield of cassava, i.e. the yield without the nutrient as

a percent ofthe highest yield with the nutrient, and the organic matter, available P and

exchangeable K contents ofthe soil in ten long-term NPK trials conducted in Asiafrom

1993 to 1996.

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369

Effect of Varieties on Soil Erosion

Cassava varieties differ in their plant architecture (mainly branching habit), height

and early vigor, which all have an effect on the rate of canopy closure and thus on soil

erosion. Canopy closure and early vigor, however, can also be affected by management

practices, particularly fertilization and plant spacing. To determine the effect of both

plant architecture and management practices on soil erosion, four cassava varieties of

distinct plant architecture were planted with three management treatments, i.e. with

fertilizers at either wide (1.0x1.0 m) or close (0.8x0.8 m) plant spacing, or without

fertilizers at close spacing. Table 6 shows the average results for three years of

cropping. As expected, the highly-branched variety, Rayong 3, had low early vigor,

resulting in slow canopy closure and low yield, but, surprisingly, this had no significant

effect on erosion. The erect non-branching variety, Hanatee, had rather good canopy

cover, also a low yield, but a similar level of erosion as the higher yielding,

intermediately branched varieties, Rayong 1 and Rayong 90. Thus, intrinsic varietal

characteristics, such as branching habit seems to have little effect on soil loss due to

erosion. However, application of fertilizers reduced erosion significantly, from 10.0 to

6.8 t/ha. Closer plant spacing markedly increased the degree of canopy cover and

increased cassava yields of Rayong 1 and Rayong 90, but it actually increased erosion

as compared to the wider spacing; this is contrary to most other trials, which generally

show that closer plant spacing decreases erosion. It may be concluded that management

practices, particularly the application of fertilizers, had a much greater effect on soil

erosion that did differences in plant architecture of different varieties.

3. Effect of Soil/Crop Management on Erosion

Management practices, such as date of planting, plant spacing, land preparation,

fertilizer application, weeding, and intercropping all may have an effect on plant growth

and yield as well as on erosion. Other practices, such as contour ridging, mulching and

the planting of contour barriers, are intended mainly to reduce erosion but these also have

an effect on yield,

a) Date ofplanting

Preliminary data from Thailand (Tongglum et al., 1997) indicate that planting

during the early dry season (Oct-Dec) markedly reduced erosion compared with planting

in the early wet season (April), because heavy rainfall in the early growth stage caused

severe erosion in the latter treatment. Planting in the early part of the dry season not

only resulted in low erosion but also in high yields, while weeding costs could be

reduced. These data need to be confirmed, but may point to several advantages of

planting cassava in the early dry season instead of the common practice of planting at the

onset of the rainy season.

370

Table 5. Effect of various crops and cropping systems on dry soil loss due to erosion

and on net income during an 8 month cropping cycle on 5% slope in

Tamanbogo, Lampung, Indonesia. Data are average values for two years

(1994-1996).

Dry soil loss Net income"

(t/ha) ('000Rp/ha)

41.92 322

26.29 570

30.64 159

29.06 804

24.31 1477

24.98 892

17.92 2488

27.61 2031

19.60 1301

Without fertilizers

Cassava

Rice-soybean

Maize-maize

With fertilizers

Cassava

Rice-soybean

Maize-maize

Peanut-peanut

Soybean-soybean

Cassava + maize + rice + soybean

"Net income = total crop value minus fertilizer costs.

b) Contour ridging

Erosion control trials conducted for many years in Jatikerto, Indonesia (Wargiono

et al., 1995; 1997), in Nanning, China (Zhang et al., 1997) and in Bac Thai, Vietnam

(Nguyen Huu Hy et al., 1997) have clearly shown that contour ridging is an very

effective way to reduce erosion. This generally also results in increased yields; however,

yields can also be depressed if cassava is planted during a dry period when ridging may

reduce soil moisture, thus effecting germination, or when too much run-off water is

retained behind the ridges resulting in waterlogging.

c) Fertilizer application

The application of fertilizers when cassava is grown on low-fertility soils,

generally stimulates early plant vigor, increases the rate of canopy closure, which protects

the soil from the direct impact of raindrops and thus reduces erosion; at the same time,

it increases cassava yields. This was one of the most effective ways to reduce erosion

in Nanning, China (Zhang et al., 1997); in Jatikerto, Indonesia (Wargiono et al., 1997);

in demonstration plots in Bac Thai, Vietnam (Nguyen The Dang et al., 1997); and on

farmers' fields in Rayong province of Thailand (Tongglum et al., 1997).

d) Intercropping

Intercropping with peanut or black bean has been shown many times to reduce

erosion in China, Vietnam, Indonesia and Thailand. Similarly, intercropping with upland

371

rice and maize, followed by mungbean, soybean or peanut, as practiced in Indonesia,

usually reduces erosion compared to cassava monocropping (Wargiono et al., 1997).

Intercropping cassava with low-growing economic crops that cover the soil surface

quickly, like watermelon, cucumber, muskmelon or pumpkin, significantly reduced

erosion and increased the total gross income (Tongglum et al., 1997).

e) Covercrops

The planting of a permanent legume cover crop, such as Mimosa envisa, under

cassava was tested in Jatikerto, Indonesia; it was found to be quite effective in reducing

soil erosion, but the cover crop also competed strongly with cassava resulting in low

yields (Wargiono et al., 1997). This would generally not be acceptable to farmers.

f) Mulch application

Application of mulch of dry grass, rice straw or maize residues among cassava

plants as a way to reduce erosion has not been studied extensively in Asia, since cutting

and carrying grass mulch is usually considered too time consuming, while crop residues

are generally used as feed or bedding for farm animals. Still, during several years of

testing in Baybay, Leyte, in the Philippines, the use of grass mulch was found to be the

most effective among various treatments in reducing erosion, while also increasing

cassava yields (Evangelio et al., 1995). In situ production of mulch, such as the

intercropping with legume species, like Crotalaria juncea, Canavalia ensiformis and

pigeon pea, which are cut and mulched at about 2 MAP, is another alternative. This

treatment had no significant effect on soil loss or yield in Nanning, China (Zhang et al.,

1997). but increased yields in Thailand (Table 3)

g) Alley cropping with leguminous tree species

Planting contour hedgerows of leguminous tree species, such as Leucaena

leucocephela, Gliricidia sepium, Flemingia congesta and Tephrosia candida among food

crops are intented mainly to improve the soil's chemical and physical characteristics when

branches and leaves are lopped-off regularly and mulched between crop plants. In

Jatikerto, Indonesia, these treatments markedly increased cassava yields (Wargiono et al. ,

1997), but in Khaw Hin Sorn, Thailand, this had no beneficial effect on yield (Table 7);

in the latter location, hedgerows of Crotalaria juncea or pigeon pea were slightly better

in this respect. In both locations these hedgerows were quite effective in reducing

erosion, either by slowing the flow of run-off water down the slope, by the application

of mulch of leaves and branches which protect the soil from rainfall impact while

improving cassava canopy cover (at least in Indonesia), or by permitting only contour

land preparation, which, over time, results in terrace formation,

h) Contour barriers of grasses

The planting of contour hedgerows of grasses, such as vetiver grass (Vetiveria

zizanioides), lemon grass {Cymbopogon citratus), citronella grass (Cymbopogon nardus),

or elephant grass (Pennisetum purpureum) are generally intended to reduce erosion by

slowing the flow of run-off water. However, they may reduce yields by occupying 10

372

20% of crop land, as well as by direct competition; or they may increase yields by the

retention of soil, fertilizers and water. Planting of contour barriers of elephant grass in

Jatikerto, Indonesia, was quite effective in reducing eroison, but generally reduced

cassava yields (Wargiono et al., 1995; 1997); it did provide, however, a good source of

animal feed. Contour barriers of vetiver grass, were found to be very effective in

reducing erosion, both in Nanning, China (Zhang et al., 1997) and in Khaw Hin Sorn,

Thailand (Table 7). While they actually increased cassava yields in Nanning. Once

well-established, vetiver grass forms a dense hedge that reduces the speed and spreads

the flow of water down the slope, allowing soil sediments to deposit behind the hedge

and water to infiltrate into the soil. When regularly cut, the vetiver grass leaves are also

a good source of in-situ mulch to be spread between cassava plants. This seems to be

one of the most promising methods to control soil erosion when cassava is grown on

slopes; it was also the method most preferred by farmers participating in Farmer

Participatory Research (FPR) trials in Vietnam (Nguyen the Dang et al., 1997) and

Thailand (Vongkasem et al., 1997); intercropping with citronella was found to be rather

effective in controlling erosion in Malaysia (Chan et al., 1994).

Thus, although cassava seems to cause more erosion than many other food crops

there are many ways to reduce erosion in cassava-based cropping systems, each having

certain advantages and disadvantages (Howeler, 1995). Which method is the most

suitable for a particular situation depends very much on the local bio-physical and socio

economic conditions, as well as on the farmer's traditional practices. Instead of

recommending one particular practice throughout the country or region, farmers should

be shown a range of practices and they should be encouraged to try out several of these

in FPR trials on their own fields before deciding on the best practice for their own

conditions. Once farmers themselves have developed an effective erosion control package

of practices, they are more likely to adopt these on a larger scale on their own production

fields.

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25.65 16.40 3.60

25.65 13.28 3.40

25.94 15.47 7.92

27.48 18.45 7.75

23.99 14.83 7.61

21.17 12.27 6.04

Table 7. Effect of various soil/crop management treatments on cassava yield and erosion in

cassava grown on 5% slope in Khaw Hin Sorn, Prachin Buri, Thailand, in 1995/96.

Cassava Cassava Dry

root top soil

yield yield loss

Treatments (t/ha) (t/ha) (t/ha)

1. Cassava monoculture, no barriers 32.53 22.67 10.01

2. Cassava monoculture, vetiver (native) hedgerows"

3. Cassava monoculture, vetiver (Sri Lanka) hedgerows"

4. Cassava monoculture, Crotalaria juncea hedgerows"

5. Cassava monoculture, pigeon pea hedgerows"

6. Cassava monoculture, Leucaena leucocephala hedgerows"

7. Cassava monoculture, Gliricidia sepium hedgerows"

8. Cassava (Rayong 1) intercropped with cassava (Rayong 60) 27.39 26.32 10.07

" The hedgerows occupied about 20% of the total area, resulting in lower yields.

REFERENCES

Chan, S.K., S.L. Tan, H. Ghulam Mohammed and R.H. Howeler. 1994. Soil erosion control in

cassava cultivation using tillage and cropping techniques. MARDI Res. J. 22:55-66.

Evangelio, F.A., F.G. Villamajor Jr., A.G. Dingal, J.C. Ladera, A.C. Medellin, J. Miranda and

G.E. Sajise Jr. 1995. Recent progress in cassava agronomy research in the Philippines. In:

R.H. Howeler (Ed.). Cassava Breeding, Agronomy Research and Technology Transfer in Asia.

Proc. 4th Regional Workshop, held in Trivandrum, Kerala, India. Nov 2-6, 1993. pp. 290

-305.

Evangelio, F.A. and J.C. Ladera. 1997. Recent progress in cassava agronomy research in the

Philippines In: R.H. Howeler (Ed.). Cassava Breeding, Agronomy and Farmer Participatory

Research in Asia. Proc. 5th Regional Workshop, held in Danzhou, Hainan, China. Nov 3-8,

1996.

Howeler, R.H. 1995A. Agronomy research in the Asian Cassava Network-Towards better

production without soil degradation. In: R.H. Howeler (Ed.). Cassava Breeding, Agronomy

Research and Technology Transfer in Asia. Proc. 4th Regional Workshop, held in Trivandrum,

Kerala, India. Nov 2-6, 1993. pp 368-409.

Howeler, R.H. 1995B. Results of soil analyses in Asia. In: R.H. Howeler (Ed.). Cassava

Breeding, Agronomy Research and Technology Transfer in Asia. Proc. 4th Regional

Workshop, held in Trivandrum, Kerala, India. Nov 2-6, 1993. pp. 447-464.

Howeler, R.H. 1996. Diagnosis of nutritional disorders and soil fertility maintenance of cassava.

In: G.T. Kurup et al. (Eds.). Tropical Tuber Crops. Problems, Prospects and Future

Strategies. Oxford and IBH Publishing Co. Pvt. Ltd., New Dehli, India. pp. 181-193.

Nguyen Huu Hy, Pham Van Bien, Nguyen The Dang and Thai Phien. 1997. Recent progress

in cassava agronomy research in Vietnam. In: R.H. Howeler (Ed.). Cassava Breeding,

Agronomy and Farmer Participatory Research in Asia. Proc. 5th Regional Workshop, held in

375

Danzhou, Hainan, China. Nov 3-8, 1996.

Nguyen The Dang, Tran Ngoc Ngoan, Le Sy Loi, Dinh Ngoc Lan and Thai Phien. 1997. Farmer

participatory research in cassava soil management and varietal dissemination in Vietnam. In:

R.H. Howeler (Ed.). Cassava Breeding, Agronomy and Farmer Participatory Research in Asia.

Proc. 5th Regional Workshop, held in Danzhou, Hainan, China. Nov 3-8, 1996.

Putthacharoen, S. 1993. Nutrient Removal by Crops and Nutrient Loss by Erosion in Cassava in

Comparison with that of Other Crops. MSc. Thesis, Kasetsart Univ., Bangkok, Thailand. 103

p. (in Thai).

Tongglum, A., V. Pornpromprathan, T. Nual-on and R.H. Howeler. 1997. Recent progress in

cassava agronomy research in Thailand. In: R.H. Howeler (Ed.). Cassava Breeding, Agronomy

and Farmer Participatory Research in Asia. Proc. 5th Regional Workshop, held in Danzhou,


Vongkasem, W., K. Klakhaeng, S. Hemvijit, A. Tongglum, S. Katong and D. Suparhan. 1997.

Farmer participatory research in cassava soil management and varietal dissemination in

Thailand. In: R.H. Howeler (Ed.). Cassava Breeding, Agronomy and Farmer Participatory

Research in Asia. Proc. 5th Regional Workshop, held in Danzhou, Hainan, China. Nov 3-8,

1996.

Wargiono, J., B. Guritno, Y. Sugitoand Y. Widodo. 1995. Recent progress in cassava agronomy

research in Indonesia. In: R.H. Howeler (Ed.). Cassava Breeding, Agronomy Research and


India. Nov 2-6, 1993. pp. 147-174.

Wargiono, J., Kushartoyo, Suyamto H. and B. Guritno. 1997. Recent progress in cassava

agronomy research in Indonesia. In: R.H. Howeler (Ed.). Cassava Breeding, Agronomy and

Farmer Participatory Research in Asia. Proc. 5th Regional Workshop, held in Danzhou,


Zhang Weite, Lin Xiong, Li Kaimian and Huang Jie. 1997. Farmer participatory research in

cassava soil management and varietal dissemination in China. In: R.H. Howeler (Ed.). Cassava

Breeding, Agronomy and Farmer Participatory Research in Asia. Proc. 5th Regional

Workshop, held in Danzhou, Hainan, China. Nov 3-8, 1996.

376

FARMER PARTICIPATORY ADAPTATION AND ADOPTION OF

CONTOUR HEDGEROWS FOR SOIL CONSERVATION

Sam Fujisaka1

ABSTRACT

From 1987 through 1992 a team of on-farm researchers worked at Claveria in northern

Mindanao to improve the productivity and sustainability of the local upland rice and maize-based

agroecosystems. Adaptive research goals were to improve crop productivity, control soil erosion,

and improve nutrient cycling. A "strategic" goal was to develop methods by which research

programs could work with farmers to develop locally appropriate and adoptable innovations. We

used contour hedgerow systems as a general technology to control soil erosion; worked with

farmers on their adaptation of the technology; and eventually our results included lessons for

farmer-participatory research, technology development, and technology transfer.

INTRODUCTION

Soil erosion and soil nutrient depletion are major problems in cultivated upland

areas in southeast Asia. Agroforestry technologies developed to address these problems

include vegetative strips to reduce soil erosion on sloping lands and use of legume tree

biomass to improve soil nutrient cycling (Huxley, 1986; Kang and Wilson, 1987; and

Young, 1986, 1987). Innovations, however, have not been widely adopted because of

technical problems and lack of fit with farmers' circumstances. With a goal of increasing

the local appropriateness and, therefore, adoption rates of such technologies, recent

approaches have actively involved farmers in the development of such conservation

technologies (Fujisaka, 1989a; Getahun and Njenga, 1990; Pahlman, 1990; Raintree and

Hoskins, 1988; Roucheleau, 1987; and Scherr, 1991).

This paper describes a case in which farmers adapted a "knowledge-intensive"

technology of contour hedgerows to fit their needs and local circumstances. Contour

hedgerows harness erosive forces (plowing and rainfall runoff) to naturally form terraces.

The technology is appropriate for areas with sloping land, use of tillage, intense rainfall,

and land scarcity.

Researchers from the International Rice Research Institute (IRRI) and the

Philippines' Department of Agriculture facilitated farmer-to-farmer training and farmers'

adaptation of contour hedgerows in Claveria, Misamis Oriental province. Claveria

farmers were able to: 1 . modify hedgerow establishment methods in order to substantially

reduce labor requirements (Fujisaka, 1993); and 2. select locally suitable species for use

in the hedgerows (Fujisaka et al., 1994).

LOCATION AND METHODS

Claveria is an on-farm research site located at 390 to 550 m above sea level. A

1 Centro Internacional de Agricultura Tropical (CIAT), Apartado Aereo 6713, Cali, Colombia.

377

mean of about 200 t/ha/year of soil are lost from slopes given that rainfall is moderate

to high and about 59% of the cropping occurs on land with > 15% slope. Average

rainfall is 2200 mm/year, with 5 to 6 wet months (July-Dec > 200 mm/month) and 2 or

3 drier months (< 100 mm/month). Soils are classified as oxic Dystropepts, ranging

from clays to silty clay loams; these are acidic (pH 4.5-5.8) with low available P (1 .3-4.7

ppm), low CEC (6-12 me/lOOg), medium to high Al saturation (1 1-51 %), and moderate

organic matter (3.16%) and exchangeable K (113.1 ppm).

Farmers settled in the area in the 1950s following deforestation by logging and

used some of the resulting grasslands for large-scale cattle ranching in the 1960s and

1970s. Agriculture is now semi-permanent with all lands de facto or de jure owned;

some land fallowing is practiced; and lands are prepared by oxen-drawn plow. Main

crops are traditional and improved maize, traditional and improved upland rice, cassava,

and, on smaller plots, tomato for commercial sale. Farmers adopting contour hedgerows

grow these same crops in the alleys formed between hedgerows.

Farmer-to-farmer procedures were used to introduce contour hedgerows to

Claveria farmers (Fujisaka, 1989b). In 1987, six farmers who reported yield declines

due to soil erosion and two IRRI technicians learned from farmers in the non-government

World Neighbors project in the neighboring island of Cebu how to use an A-frame to

establish contour lines, construct contour bunds and ditches, and plant hedgerows. The

"original" hedgerows were comprised of one or two rows of the leguminous tree

Gliricidia sepium, and one or two rows of Napier grass, Pennisetum purpureum.

These farmers and later adoptors trained more than 200 farmers from 1987

through 1991 using the farmer-to-farmer techniques applied in Cebu. Approximately 80

Claveria farmers adopted some form of contour hedgerows by late 1992. Researchers

at the site recorded field areas and slope, length of hedgerows, area occupied by

hedgerows, heights of embankments formed over time, labor used for establishment,

farmers' technical changes and adaptations, and effectiveness of methods. Open-ended

interviews were used to obtain farmers' perceived benefits, associated problems, and

evaluations of technology components. Slopes of alleys (areas between hedgerows) were

calculated based on measurements of the embankments, assuming that hedgerows were

placed at 1 m vertical intervals.

Fifty-five of the adoptors were again interviewed and their 60 hedgerow fields

monitored at the end of 1992. Many later adoptors (within the 1987-92 period) relied-

solely or combined with other species-upon naturally occuring "weeds" in their

hedgerows. We identified these in each of 57 fields (three fallowed fields were not

included). Forty-six of the fields with hedgerows utilized at least some weeds. For each

of these fields and during the main cropping season, ten 10-meter lengths of hedgerow

were randomly selected across each field; the five weed species with the greatest number

of individuals were identified, with actual counting done if there was any doubt as to

378

which weeds were the most frequent. "Main" weeds presented include any listed as one

of the five most frequent in any of the 57 fields monitored. Weed species encountered

in the natural hedgerows were compared to major weeds in upland rice and maize

identified by farmers in an earlier study.

Farmers also evaluated the contour hedgerows. We asked, "How do you now

evaluate your contour hedgerow system?" The question was intentionally open-ended to

allow answers reflecting what was important to each individual, e.g. hedgerow functions,

problems, and/or species choice. No specific or further prompts were used. Each

response is presented in terms of its percentage of the total number of answers given.

Farmers who did not adopt the technology after farmer-to-farmer training were

interviewed about reasons for non-adoption. Slopes of the lands of adoptors and non-

adoptors were measured and compared.

Crop yields on farmers' fields with and without contour hedgerows were

monitored in the wet season of 1991, a severe drought year, by taking crop samples.

Other data on yields and on soil erosion rates with and without contour hedgerows were

provided by other researchers working at the site.

RESULTS

Contour Hedgerow Adoption in Claveria

By the end of 1990, each of 75 adoptors in Claveria contoured a mean of 0.7 ha

and established 761 m of hedgerow per field. Mean slope of fields was 22%. On

average, hedgerows occupied 9% of the field areas on which they were established.

Because farmers placed one hedgerow per meter of vertical drop within a field, length

of hedgerows per ha increased as initial field slope increased, with a corresponding

increase in labor required, although this was influenced by evolving hedgerow

establishment methods.

Terracing took place rapidly after hedgerow establishment. For nine fields

established in 1987, mean heights of hedgerow embankments were 36 cm after one year,

44 cm after two years, and 49 cm after three years, indicating that slopes of alleys

decreased from an initial mean field slope of 16% to 9% after one year, 8% after two

years, and 7% after three years. Furthermore, 75% of the embankment formed after

three years had already formed in the first year, suggesting that alleys reached relatively

stable slopes after one year. Height of terrace embankments in front of the hedgerows

tended to increase as slope increased.

Farmer Modification of Hedgerow Establishment Methods

Working as a group, farmers established hedgerows on 10 parcels of land having

an average size of 0.8 ha in the first year. Labor for establishment (average 29 days/ha

with 55% for shoveling) and hedgerow density (673 to 1555 m/ha) depended on field

slope and resulting variation in distances between strips. Farmers established 17 to 57

379

m/person/day of hedgerow; labor to establish hedgerows was least on fields already

plowed after initial rains and greatest on grassy fallowed fields on which hedgerows had

been established prior to the rains.

In 1987 farmers spent an average 14 hours per 100 meters of hedgerow

established, and 29 days of labor per ha on which hedgerows were placed. By 1990

farmers needed only 8 hours per 100 meters and 16 days per ha (Table 1). The original

hedgerow establishment method consisted of using the A-frame to determine contour

lines, double plowing to create a bund, shovel work to reinforce bunds, and planting of

a double row of trees plus a single row of grasses. Farmers saved labor by reduced

plowing, virtual elimination of shovel work, planting of either trees or grasses rather than

combinations, or-by 1989 and 1990-the staking of contour lines (usually but not always

bunded), which were then left to be covered by "weeds" or native grasses (discussed

below). There were no differences among farmers' various hedgerow establishment

methods in terms of embankment formation and terracing, but establishment labor per

ha also decreased with increasing field size, suggesting some "economy of scale".

Table 1. Farmer contour hedgerow adoption and labor used for hedgerow

establishment, Claveria, Misamis Oriental, Philippines, 1987-1990.

1987 1988 1989 1990

Number of adoptors 14 13 29 6

Mean labor (hrs) per 100 m

of hedgerow 14 14 10 8

Farmers' Evolving Hedgerow Species Choice

Following what they learned from farmers in Cebu, initial adoptors in 1987 and

1988 planted hedgerows largely of Glyricidia sepium and Pennisetum purpureum.

Farmers gradually shifted species in the hedgerows. Those adopting in 1989 planted

mulberry and Flemingia congesta in addition to G. sepium; and planted Setaria spp and

Panicum maximum (Guinea grass) in addition to P. purpureum. Farmers also started to

develop contour hedgerows of purely natural vegetation in 1989. In 1990 and 1991, new

adoptors planted mainly Setaria or Guinea grass, or developed hedgerows of weeds.

Other less used species included Chloris sp (signal grass), Stylosanthes spp, Helianthus

annuus (wild sunflower), "ginseng" (an unidentified medicinal plant), cassava, taro,

coffee, and fruit trees.

Table 2 shows the species planted (or utilized in the case of natural weed contour

hedgerows) in the hedgerows by year of establishment (1987-1992). Entries per column

380

total more than the number of fields as more than one species were often planted or

utilized. By the end of 1991 and for 60 fields belonging to 55 hedgerow adoptors: 47%

included G.sepium, 38% included P.purpureum, 32% included Setariaspp, 20% included

P. maximum, 17% included mulberry, and 18% were of weeds alone. Adoption of

G.sepium and of P.purpureum decreased; and adoption of Setaria, P. maximum, and weed

strips increased over the study period. Mulberry adoption was high only in 1989. For

the 15 of 60 fields established in 1990 and 1991, only one included trees (mulberry), 8

fields had planted grasses, and 7 had weeds alone. Farmers evaluations of their different

hedgerow species are shown in Tables 3 and 4.

Farmers had several sources of seed or planting material. They used cuttings of

locally indigenous G.sepium, P.purpureum and H.annuus. Seed of F.congesta came

from a stand of trees planted by a farmer several years prior to our work in the area.

IRRI conducted trials on forage species and small quantities of seed of Chloris sp,

Stylosanthes spp, and P. maximum were given away upon request. Others later obtained

seeds of these forages from the first farmers planting them in hedgerows. Mulberry

cuttings came from a 10 ha area where trees had been planted in the mid-1980s for a

government silkworm project. Farmers had tried to eradicate the mulberry; and their

lack of success meant that there was ample planting material when farmers were again

induced to rear silkworms. Although farmers had free access to researchers' forage

trials, their selection and testing reflected their own search for useful and suitable

hedgerow species.

The main species found in the contour hedgerows utilizing natural, in situ weeds

(and in hedgerows combining both planted species and weeds) were Pennisetum

polystachion (in 67% of 57 fields with hedgerows), Paspalum conjugatum and Borreia

laevis (58% each), Ageratum conyzoides (44%), Chromolaena odorata (42%), Digitaria

longiflora (37%), Mimosa invisa (32%), Rottboellia cochinchinensis (25%), Hyptis

suaveolens (25%), and Imperata cylindrica (23%). Twenty-two other weeds occured as

a main weed in farmers' hedgerows, but each of these in less than 10% of the

hedgerows. Only 1 1 % of fields had hedgerows with no natural grasses or weeds (Table

5).

A previous study (Elliot and Moody, 1986) elicited farmers' worst weeds in terms

of effort needed to control each one. These were, in order, R. cochinchinensis,

D. longiflora, P.polystachion, B. laevis, M. invisa, I. cylindrica, P.conjugatum and

Brachiaria mutica. These same problem weeds—and especially creeping weeds such as

D. longiflora and P.conjugatum-hdve provided a good alternative for farmers interested

in soil erosion control and in reducing hedgerow establishment costs, but not interested

in other supposed "multipurpose" uses (i.e., fodders, green manures, or cash crops such

as coffee or fruit trees) of hedgerow species. Farmers knew that they needed to slash the

weedy hedgerows before seeding in order to avoid creating additional weed problems in

their crops.

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Table 3. Farmer evaluations of napier grass (Pennisetum purpureum) and Gliricidia

sepium planted in hedgerows, in Claveria, Philippines in 1990.

Number of farmers

Pennisetum purpureum

Positive evaluations

Controls soil erosion 15

Provides animal feed 11

Grows easily 4

Competition not a problem if maintained 1

Negative evaluations

Crops near hedgerows were stunted and yellowed 11

Competitive and too vigorous 6

Roots spread into alleys and make plowing difficult 3

Deteriorates with constant pruning 2

Shelters rats 1

Total 54

Gliricidia sepium

Positive evaluations

Source of organic fertilizer 16

Improves the soil and gives a higher yield 1

Provides feed for animals 1

Reduces soil erosion 1

Negative evaluations

Caused shading if not maintained 1

Difficult to plow when roots spread to the alley 1

Total 21

383

Table 4. Farmer evaluations of other contour hedgerow species in Claveria,

Philippines.

Number of farmers

Mulberry prevents soil erosion and provides income 13

Will extend mulberry hedgerows to other parcels 2

Flemingia congesta does not compete with the alley

crop and is easy to maintain 1

Grasses control soil erosion and provide fodder 5

Grasses hold the soil better than trees 2

S.guyanensis is good, but competes with crops 1

Andropogon sp is good, but spreads into the alley 1

Roots of Desmanthus virgatus do not hold the soil 1

Pineapple holds the soil and provides cash and food 2

Taro holds the soil and provides cash and food 1

Sunflower holds the soil, provides green manure, but can

be a weed problem 1

Total 30

Adoptors' Evaluations of the Technology

Ninty-six percent of the 55 adoptors interviewed in 1992 viewed hedgerows as

a way to control soil erosion (Table 6). Almost half (45%) mentioned production of

fodder-especially in the dry season-for their draft animals as a desirable function of the

hedgerows. Fifteen percent reported that biomass from G.sepium could be used as a

green manure for the alley crop, although only three cases during one rice growing

season (1991) of biomass use for green manure were observed. The same percentage of

farmers thought that inorganic fertilizers could be applied to their alley crops without

being washed downslope by rains. A few farmers reported that natural grass strips were

easy to maintain (and survived drought periods better than introduced grasses); while

others thought that hedgerow pruning and deep plowing in the alley solved the problem

of crop-hedgerow competition.

On the other hand, 35% of the farmers reported that hedgerows—especially those

with grasses such as P.purpureum-compeled with the crop grown in the alley. Our

observations made it clear that rice and, to a lesser degree, maize were very affected by

such competition for moisture and soil nutrients (and light in the case of trees in the

hedgerows). Competition between hedgerow and crop led to farmer testing and selection

of species (including weeds) other than the orignal P.purpureum.

384

Almost a third (31 %) of the farmers found it necessary to fallow land on which

they had established contour hedgerows due to combinations of soil nutrient depletion and

competing demands and higher opportunities from their flatter lands and from off-and

non-farm income sources. Continued fallowing of adopters ' fields was noteworthy

because researchers had regarded contour hedgerows as a possible way to sustain

permanent cropping. Some landowners fallowed parcels on which they had established

contour hedgerows, and then selected and became tenant farmers on other parcels-in a

unique form of shifting cultivation.

Fallowed fields have traditionally been an open-access grazing resource in

Claveria. Neighbors' staked or freely grazing animals were mentioned as a problem by

18% of the hedgerow adopters. We observed that grazing was especially a problem in

cases in which forage species preferred by animals were planted in the hedgerow.

Destruction of hedgerows by neighbors' cattle is a "social" problem in that the solution

would require community or group cooperation and action.

About a fifth of the farmers planted mulberry trees in their hedgerows after a

silkworm project was started in the area. By 1992, however, the project was no longer

in business and 16% of the adopters thought that mulberry was useless without the

project.

Non-Adoptors

Farmers who did not adopt hedgerows after attending farmer-to-farmer training

sessions gave their reasons. These were lack of labor or draft animals or competing

demands for labor on non-sloping areas for farmers with large proportions of such lands

or for off-farm and non-farm activities (Table 7). Although a few non-adoptors

mentioned that their tenant status barred adoption, about 16% of adoptors were share

tenants.

In light of non-adoptors' responses, adopters' and non-adoptors' land sizes and

slopes were measured. Differences between total land holdings and between percent

slopes on sloping lands did not differ significantly between the groups, but a significantly

higher proportion of adopters' lands was sloping (> 7% slope) compared to that of non-

adoptors' (Table 8).

Crop Performance and Soil Erosion

Yields of maize and rice on farmers' fields with or without contour hedgerows

were similar in the wet season of 1991, a year of severe drought (Table 9). The lack

of response to hedgerow adoption was not discouraging because hedgerow species are

susbtiantally more competitive for moisture than rice or maize in drought periods. Data

from researcher designed and managed trials in Claveria also showed that cereal yields

were similar with and without hedgerows when leaf prunings from the hedgerows were

385

not applied to the crop, although there was a substantial maize yield increase following

incorporation of Cassia spectabilis biomass (Mercado et al., 1991).

Soil erosion was monitored by researchers in controlled experiments. In normal

rainfall years, approximately 200 t/ha were lost on open slopes and 20 t/ha from fields

with contour hedgerows. In the 1991 drought year less soil was lost, but some 40 t/ha

were still lost on open slopes and 4 t/ha on fields with contour hedgerows (Garrity et al.,

1993).

Table 5. Main "weeds" in 57 contour hedgerows", Claveria, 1992.

Weed species % of Hedgerows Worst weeds2

No "weeds" used in hedgerows

Pennisetum polystachionv

Paspalum conjugatum

Borreria laevis

Ageratum conyzoides

Chromolaena odorata

Digitaria longiflora

Mimosa invisa

Rottboellia cochinchinensis

Hyptis suaveolens

Calopogonium mucunoides

Imperata cylindrica

Bidens pilosa

Digitaria setigera

Mimosa pudica

Sida rhombifolia

Elephantopus tomentosus

{Brachiaria mutica)

11

67

58

58

44

42

37

32

25

25

23

23

21

16

14

12

12

(2)

3

7

4

(7)

" Three fallowed or abandoned contour hedgerow fields not included.

21 Eight most difficult to control weeds in farmers' order.

31 "Main" weeds were among the five most frequently occurring in the given % of

hedgerows; 22 other species were each one of the five highest occurring, but each in

less than 10% of the hedgerows.

386

Table 6. Farmers" evaluations of contour hedgerows established in 1987-1991, in

Claveria, Misamis Oriental, Philippines.

Evaluation % of farmers

Postitive27

Hedgerows control soil erosion 96

Hedgerows provide fodder 45

G.sepium provides green manure 15

Inorganic fertilizer can be applied and not lost downslope 15

Natural grasses are easy to maintain 9

Negative37

Hedgerows (especially grasses) compete with crop 35

Fallowed due to poor soil, flatter lands, off/non-farm work 31

Neighbors' animals graze and destroy hedgrows in dry season 18

Mulberry serves no purpose without silkworm project 16

" n = 55

27 Other positive evaluations: Setaria is good for erosion control and fodder; hedges are

not crop-competitive if pruned and plowing in the alley is deep; and G.sepium can be

used for fence stakes

?/ Other negative evaluations: crop stunted in upper rows due to soil scouring; pruning

hedgerows required too much labor; contours on uneven slopes mean uneven alley

widths, which are difficult to plow

Table 7. Trained farmers' reasons for non-adoption of contour hedgerows

(140 observations).

No. of observations

Work demands on non-sloping or lowland parcels 40

High labor for contour hedgerow establishment 27

Off-farm and non-farm work opportunities 18

Lack of draft animal 16

Lack of capital for labor and inputs 12

Left the area 10

Does not own the land 7

Miscellaneous 10

Total 140

387

Table 8. Areas and slopes of lands of adoptors and non-adoptors of contour

hedgerows in Claveria, Philippines.

Adoptor Non-adoptor

Total land area (ha)

area of flat land (ha)

area of sloping land (ha)

% slope of sloping land

1.70 1.68

0.43 0.79

1.27 0.89

21 25

Table 9. Farmers' yields of rice and maize (t/ha) of fields with and without contour

hedgerows in Claveria, Philippines, wet season 1991 (number of cases in

parenthesis).

With hedgerows Without hedgerows

Rice 0.68 (6) 0.77 (16)

Maize 1.22 (12) 1.23 (10)

CONCLUSIONS

Findings suggest that a permanent, sustainable contour hedgerow system would

have several features.

1. Sufficient soil tillage and rainfall is needed to cause both soil erosion as a problem and

to enable natural terracing to take place as a solution.

2. Farmers should have mostly sloping land and a lack of off- and non-farm labor

opportunities if they are to invest in their land.

3. The land frontier needs to be closed if farmers are not to shift more profitably to other

parcels.

4. Hedgerow species are needed that survive the dry season, do not overly compete with

the crop in the alley, and are fairly easy to maintain.

5. Farmers should be able to apply inorganic fertilizers to the alley crops or should have

sufficient labor to apply the biomass from perennial legumes planted in the hedgerows

to maintain soil fertility.

388

6. A social system is needed in which community members cooperate in the control of

grazing animals in a way that animals are not allowed to graze and destroy hedgerows.

Perhaps more importantly, both researchers and farmers contributed to developing

appropriate and adoptable technologies. Researchers facilitated initial farmer-to-farmer

technology transfer and monitored farmers' progress in solving problems. Farmers

modified the basic technologies-use of the A-frame and vegetative contour strips—in

order to save labor and reduce crop-hedgerow competition. Adoptors greatly reduced

soil erosion on their sloping lands, but now need to solve the problem of soil nutrient

depletion.

REFERENCES

Elliot, P. and K. Moody. 1986. Weed control studies in upland rice-based cropping systems.

Unpublished paper presented at the Claveria Cropping Systems Review, held in Cagayan de

Oro City, Philippines. March 6-7, 1986.

Fujisaka, S. 1989a. The need to incorporate farmer perspectives: lessons from a comparison of

selected upland projects and policies. Agroforestry Systems 9:141-153.

Fujisaka, S. 1989b. A method for farmer-participatory research and technology transfer: upland

soil conservation in the Philippines. Experimental Agriculture 25:423-433.

Fujisaka, S. 1993. A case of farmer adaptation and adoption of contour hedgerows for soil

conservation. Experimental Agriculture 29:97-105.

Fujisaka, S., E. Jayson and A. Dapusala. 1994. Trees, grasses, and weeds: species choices in

farmer-developed contour hedgerows. Agroforestry Systems 25:13-22.

Garrity, D.P., D.M. Kummer and E.S. Guiang. 1993. The upland ecosystem in the Philippines:

alternatives for sustainable farming and forestry. In: Agricultural Sustainability and the

Environment in the Humid Tropics. National Academy of Sciences, Washington DC, USA.

Getahun, A. and A. Njenga. 1990. Living stakes: Kenyan farmers introduce an agro-forestry

technology. Forest, Trees and People Newsletter 9, 10: 38-39.

Huxley, P. A. 1986. Rationalising research on hedgerow intercropping: and overview. International

Council for Research on Agroforestry (ICRAF) Working Paper 40, Nairobi, Kenia.

Kang, B.T. and G.F. Wilson. 1987. The development of alley cropping as a promising

agroforestry technology. In: H.A. Steppler and P.K.R. Nair (Eds.). Agroforestry: A Decade

of Development. ICRAF, Nairobi, Kenia.

Mercado, A., A. Montecalvo, D.P. Garrity and I. Bashri. 1991 . Contour hedgerow systems using

Cassia spectabilis and their effect on upland rice and maize crops on sloping acid upland soils.

Agroecology Unit Paper. IRRI, Los Banos, Philippines.

Phalman, C. 1990. Farmers. perception of the sustainability of upland farming systems in northern

Thailand. The Sustainable Agriculture Newsletter 2:2:25-26.

Raintree, J.B. and M.W. Hoskins. 1988. Appropriate R&D support for forestry extension. Paper

for the FAO Consultation on the Organization of Forestry Extension, held in Bangkok,

Thailand March 7-11, 1988.

Roucheleau, D.E. (n.d.) The user perspective and the agroforestry research and action agenda.

ICRAF, Nairobi, Kenia.

Scherr, S, (Ed.). 1991. On Farm Agroforestry Research. A special issue of Agroforestry Systems

15:2, 3:91-308.

Young, A. 1986. The potential of agroforestry for soil conservation. Part I. Erosion control.

Working Paper 42. ICRAF, Nairobi, Kenia.

Young, A. 1987. The potential of agroforestry for soil conservation. Part II. Maintenance of

fertility. Working Paper 43. ICRAF, Nairobi, Kenia.

389

FARMER PARTICIPATORY RESEARCH IN CASSAVA SOIL MANAGEMENT

AND VARIETAL DISSEMINATION IN CHINA

Zhang Weite, Lin Xiong, Li Kaimian and Huang Jie1

ABSTRACT

This paper mainly describes the objectives of the FPR project, the results of the RRA that

was conducted in Hainan and the demonstration plots at CATAS, as well as the demonstration and

FPR trials at the pilot sites (especially in Kongba village of Baisha county). The major existing

problems and suggestions to improve the FPR trials in the future are also presented.

INTRODUCTION

During the 4th Asian Cassava Workshop in India in 1993, a new project on

"Improving the Sustainability of Cassava Production in Asia" was first discussed and the

possibility explored of having a pilot site in Hainan, not only because of serious soil

fertility and erosion problems in cassava producing areas in the mountains of central

Hainan, but also because of the active collaboration between cassava researchers at

CATAS with agricultural officers and farmers in the area. This project proposed to use

farmer participatory research (FPR) methodologies to improve the development and

adoption by farmers of more sustainable management practices.

Objectives of the FPR Project

The objectives of this project are: a) to reconcile the short-term needs of farmers

to increase crop yields and income with the long-term objective of preserving the soil's

productivity, i.e., to provide benefits to both farmers and society; and b) the essence of

this approach is that farmers own the process: they develop the most suitable practices

for their own conditions by testing a range of options on their own fields.

Workshop on FPR Methodologies

The Nippon Foundation project organized an FPR training workshop in Rayong,

Thailand, in July of 1994, to explain about the importance of the FPR approach, and to

develop a work plan of activities for the project in each participating country. Also

included were discussions on Rapid Rural Appraisal (RRA) methods as well as practical

training in interviewing farmers. During the workshop, the Chinese participants made

a work plan for the FPR project in Hainan, as shown in Figure 1.

FPR PROJECT IN HAINAN

1. Rapid Rural Appraisal (RRA)

An RRA was conducted in Hainan from August 14 to 20, 1994. The major

' Chinese Academy of Tropical & Agricultural Sciences (CATAS), Danzhou, Hainan,

China.

390

Establish demonstration plots CATAS, March, 1994

Conduct an RRA

Select two pilot sites

Conduct formal survey

Farmers visit demonstration plots CATAS, Jan, 1995

Establish plots in pilot sites

Conduct FPR trials in pilot sites

Collect data of FPR trials

Monitore and evaluate FPR trials

Figure 1. Design ofFPR project in Hainan.

391

objectives of this RRA were:

a) To gain a better understanding of cassava production and utilization in Hainan

and to analyze the major constraints and opportunities.

b) To select two pilot sites for the FPR project.

RRA Methodololy

Before conducting the RRA, we discussed the methodology to be used in the

group and individual interviews with farmers and the type of information to be collected.

The selection of locations to be visited was based on: a) the importance of cassava in the

area; and b) the representativeness of the production and/or processing system. As such,

based on secondary information, a pre-stratification was attempted as follows: 1) lowland

vs. highland areas; 2) near vs. far away from processing factories; 3) collective/state

farm vs. "private" farm production.

In most districts or counties we first contacted the local government officials,

mainly from the Agricultural Bureau or the Agricultural Committee. They usually

provided us with secondary data about climate, soils, landscape etc, and the production

of the major crops. We also discussed the problems of cassava production, processing

and marketing as well as future opportunities. After talking with the government

officials, we were usually taken to a cassava growing village by local extension agents.

In each village, we separated our team into two groups. One group would usually

discuss socio-economic issues and processing with one group of farmers, while the

second group would discuss varieties and cultural practices with another group of

farmers; usually, about ten to fifteen farmers were interviewed in each village. Most

discussions were held in a farmer's house or in the courtyard in front of the house. Each

session lasted about one and a half to two hours. After the discussion we were often

taken to a farmer's field, where we could see different cropping systems and evaluate the

crops. Sometimes we were taken to steep mountains slopes where cassava was planted,

providing an opportunity to ask farmers questions about erosion control and maintenance

of soil fertility.

Results of RRA

In recent years, the cassava growing area in Hainan has been about 24,000 ha

with a total annual production of 320,000 ton of fresh roots; this corresponds to about

6% of total cassava production in China. In Hainan, cassava production is concentrated

in the foothills of the central mountain range, with greatest production in Baisha and

Qiongzhong counties (Figure 2), In the past decade, cassava production area and yield

have fluctuated for several reasons. The decline in cassava area and production in

Hainan is mainly due to the aggressive promotion of other more valuable crops, like

rubber and fruit trees, as well as the absence of a significant expansion of cassava

processing facilities. While in Guangdong and Guangxi cassava further-processing into

392

glucose, MSG, maltose, alcohol and sorbitol is being promoted, in Hainan the processing

is still confined mainly to production of raw starch, using rather antiquated processing

facilities. However, farmers reported that during the past couple of years the cassava

area may have expanded again due to increasing prices as well as problems in the

transport of competing sugarcane. In the counties visited, cassava was generally the third

or fourth most important crop after rubber, rice and/or sugarcane (Table 1).

Hainan has a tropical and sub-tropical climate and is influenced by tropical

monsoons and typhoons, but with sunshine all year round. Its annual mean rainfall is

1500-2000 mm, 75-90% of which is concentrated during the rainy season of May to

October. Sometimes the precipitation per hour reaches 80-100 mm, which is a major

factor causing high levels of soil erosion. The annual mean temperature is 23-25°C. In

Hainan, being located between 18 and 20°N, cassava can be planted year-round without

danger of frost but with occasional short-term cool temperatures of 4-7°C during the

winter months, especially in the northwestern region and the northern part of the central

region; however, this does not affect cassava yields. Cassava is planted in Jan-March in

most of Hainan, but planting is delayed to March-April in the western part of the island

because of drought. Meanwhile, Hainan is the only place in China where cassava

pollination and hybridization can be successful.

In Hainan the cropping area per family is similar or slightly larger than in

Guangdong and Guangxi, except in Kongba village of Qifeng town where farmers

cultivate rather large areas by planting crops also on illegal land with steep slopes.

Moreover, in that area most farmers also manage 0.5-1 ha of rubber trees. Thus, time

for attending the crops is limited to 4-5 hours a day, usually in the afternoon. This

explains the prevalence of cassava monocropping, the less intensive management of the

crop and the use of herbicides in some locations.

Table 2 shows that cassava is grown mainly on gentle slopes with some

production on very steep slopes (up to 100%), especially in Tongzha city. Cassava in

Hainan is seldom grown on terraced fields except on State Farms; in contrast, rubber is

often planted on narrow terraces in the mountains. Cassava is generally planted as a

monocrop, although some intercropping with maize or peanut, or with maize plus sweet

potato was found; in some places the crop is also rotated with sugarcane. In Baisha and

Tongzha counties cassava is sometimes grown between young rubber or fruit trees.

Where cassava is grown on steep hillsides, the land is usually prepared only by

making individual planting holes of 10 x 20 cm with a hoe, after slashing and burning

the weed or bush vegetation (Table 3). On more gentle slopes the land is prepared by

buffalo or oxen, usually 1-2 plowings followed by 1-2 rakings. Ten to twenty cm long

stakes are planted horizontally 6-10 cm deep in each planting hole, spaced at random or

at 0.6 x 0.6 or up to 0.8 x 0.8 m. Plant populations are very high and farmers think that

this may be useful for reducing soil erosion. Depending on the type of previous

vegetation, the land clearing, soil preparation and cassava planting may take up to 15

393

man-days/mu (225/ha). On the Bayi state farm and in Kongba village, farmers spray

with pre-emergent and/or contact herbicides after planting, followed by one hand weeding

at 2-4 MAP. In other areas weeds are controlled with a hoe or knife, while in Longtang

town fields are weeded using a buffalo and plow.

In the mountainous areas of Hainan, fertilizer and/or FYM are seldom applied

to cassava, or are applied only after the second crop. Farmers often reported that yields

increase from the first to the second year of cropping due to the slow decomposition of

the previous fallow vegetation, but yields decrease again in the third and subsequent years

due to nutrient extraction and erosion. Thus, 2-3 crops of cassava are usually rotated

with sugarcane or the land is returned to fallow for 1-2 years. If cassava cultivation

continues beyond two years, farmers usually apply some urea, SSP or 15-15-15

fertilizers, either at planting or at 2-3 MAP.

In most areas of Hainan, cassava is harvested in Nov to Dec, but in some cases

this extends to Feb or even March. In the highland area of Tongzha city some farmers

leave cassava for a second cycle, harvesting only after about 18-20 months due to labor

shortage or because the crop did not grow well. If a starch factory is nearby, such as

in Maoyang and Maoqui towns of Tongzha and in Hongdao town of Qiongzhong county,

cassava is mainly sold as fresh roots (Table 4). But in the absence of a nearby factory,

cassava is chipped and dried; in the Bayi state farm and in Qifeng most of this is sold to

traders, while in Longtang town the chips are ground to a powder in a local mill and this

is fed mainly to the farmer's own pigs or is sold at the local market. Some of the chips

are taken to the animal feed mill in Wenchang county. In Hainan, on the average, 80-

90% of cassava is sold off-farm. In many areas, especially near urban centers or main

roads, on-farm pig feeding is highly lucrative. It was estimated that cassava-based pig-

feed (mixed on-farm) is 15-25% cheaper than commercial pig feed. With the current

strong economic development, especially around the larger industrialized cities, demand

for pork is very strong. In China, pork is the animal protein most consumed.

Economic data show that labor requirements for cassava production in Hainan are

higher than on the mainland. It ranges between 12-20 man-days/mu (180-300/ha). To

a large extent this can be explained by the fact that cassava fields are on steeper slopes,

farther away from the village and because of climatic conditions chip drying takes longer.

Cassava income (labor not accounted for) ranges from Y250-300/mu. Although

sugarcane is often used as a crop alternative, and has a higher income (Y300-400/mu),

in several areas there were demand problems. Also, cane, once harvested, needs to be

factory processed at once. Cassava, on the other hand can be chipped and stored, and

has more utilization alternatives. As such, these are typical criteria entering the farmer's

decision-making process regarding crop choices.

In Hainan most farmers had mixed feelings about cassava. On the one hand they

like the crop because it is well-adapted to the local soil and climatic conditions, it is easy

to grow with a minimum of inputs and it gives a quick return on labor; the harvest and

I

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Table 1. Secondary data of Hainan province (1994).

Bahyi State F. Bayi State F. Baisha Tongzha Qiongzhong Dingan

Tongshan Production County city county county

branch Team #2 Longtang

town

LatitudeCN) 19° 30' 19° 30. 19° 20. 18° 45. 19° 5. 19° 25.

Altitude(masl) < 150 <150 150-300 300-500 250-500 100-200

Soils Hapludult Hapludult yellow-red rocky rocky dark

Landscape

Hapludult Paleustult Paleustult Hapludult

-general hilly hilly hilly mountain hilly-mount. 60% upland

40% irrig.

-cassava on flat and on flat and on flat and on steep on gentle onflat and

Climate

steep slopes steep slopes gentle slopes slopes slopes gentle slopes

Average temperature (°Q 23.0-23.5 23.0-23.5 23.5-24.0 22.5 22.0-22.5 22.0-23.0

Absolute minimum temp.

Mean minimum temperature 5-7 5-7 4-5 4-5 5-7

Absolute maximum temp.

Mean maximum temperature

Rainfall (mm) 1,600-1,800 1,600-1,800 1,600-1,800 > 2,400 2,000-2,400

No. of frost-free days 365 365 365 365 365 365

Typhoon incidence medium medium low low medium high

Main crops (mu)"

rice - irrigated 1,416 30,500 72,773 15,600

- upland 4,032 3,087

cassava 2,500 300 36,778(#3) 15,748 42,012 4,100

maize 9,382 904

peanut 2,866 6,738 4,600

sugarcane 5,136 100 (#2) 8,182 14,000

fruit trees 410 10,300 4,200

vegetables 5,023 1 1 ,303

rubber 1,000 (#1) 4,800

sweet potato 239 62,937 8,050 4,500

bamboo 1,000

pineapple 14,167

Cassava yield (kg/mu)

- fresh 1,419 988

- dry 500-750

Total farm size (mu/lf)31

- upland 5.0

- irrigated 0.5

Average income (Y/person) 3,200

" 1 ha = 15 mu

21 If = Labor force

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transport of the roots is also more flexible and thus more easily organized than that of

sugarcane. But farmers complain that yields and profits are low, that it requires more

labor than sugarcane, which is harvested three times before replanting, that the transport

of fresh roots from far-away fields is hard work and that the drying of chips is a problem

during the rainy season. They also mentioned that cassava cultivation reduces the

productivity of the soil, either through nutrient extraction or erosion. Thus, they either

had to apply fertilizers to cassava or return the plot back to fallow for 1-2 years, after

which it would require considerable labor again to slash and burn the fallow for further

cropping. On the relatively fertile soils and with favorable climatic conditions, an

abundant fallow vegetation is generally produced in a short time. Farmers in the upland

areas still prefer to first plant cassava after opening up new land (often illegally).

Erosion was also recognized as a serious problem, but besides digging diversion

channels to prevent water from entering the cassava fields, very little was done to prevent

erosion. This is because of lack of labor or because they do not own the land, as in State

Farms or Township Communal Farms, where crop land is rotated among farmers or can

be used any time for rubber tree planting. Erosion was found to be very severe on the

steep slopes in Tongzha city, as well as on the gentle slopes at CATAS.

Table 5 indicates the major cassava starch and animal feed factories in Hainan,

while Figure 3 shows their locations. The small private starch factory in Qifeng town

of Baisha county is modernizing its equipment and expanding its processing capacity to

2500 ton starch/year, but this factory can operate only for three months of the year, Nov-

Jan, due to the unavailability of fresh roots during the other months. The factory will

start making contracts with farmers and pay a guaranteed price of Y140/ton (fresh root).

The state-run starch factories in Maoyang and Qiongzhong also process mainly fresh

roots, operating only from Nov-March. The latter has rather modern equipment and an

installed capacity of 10,000 ton starch/year, but due to lack of raw materials it produces

only 3000-4000 ton starch/year. The starch factory in Baisha county has a capacity to

produce 3,000 ton/year, but actually produces only 300 t/year. Most of these state- or

county-owned starch factories use old equipment, have too much personnel, and, in

general, are poorly managed, resulting in high product costs and financial losses. While

all are producing below capacity due to lack of raw materials, they do not seem to

compete aggressively with each other to secure this raw material; this is resulting in

stagnating prices and a reduction in cassava area. Hainan needs about 15,000 ton

starch/year, mainly for the food, candy and card board industries. Besides the two large

factories in Qiongzhong and Qiongshan counties there are another seven starch factories

still operating in Hainan, but with a total capacity of less than 12,000 ton starch/year

(Table 5).

Without exception, all managers of starch factories ranked lack of raw material

and lack of capital as the top two constraints. Typically, state-run factories face worse

problems than private-run factories, especially regarding technology, working capital, and

400

• - cassava starch factory

■ = animal feed factory

Figure 3. Location ofcasava starch and animalfeedfactories in Hainanprovince (see Table 5).

401

Table 5. Major cassava starch and animal feed factories in Hainan province.

Factory Location" Capacity

(t/year)

1 . Qiongzhong Starch Factory Qiongzhong county6.000*21

2. Dazhipo Starch Factory Qiongshan county 6,000*

3. Baisha Starch Factory Baisha county 3,000*

4. Maoyang Starch Factory Tongzha city 3,000*

5. Nankun Starch Factory Tunchang county 3,000*

6. Baoting Starch Factory Baoting county 2,000

7. Dingan Starch Factory Dingan county 2,000

8. Lixiegu Private Starch Factory Baisha county 1,000*

9. Xishui Starch Factory Baisha county 500

10. Longjiang Starch Factory Baisha county 500

1 1 . Wanchong Starch Factory Ledong county 500

12. Fenglai Starch Factory Wenchang county 500

13. Shishan Starch Factory Qiongshan county 500*

14. Songtao Starch Factory Qiongzhong county 500*

15. Yangjiang Starch Factory Qionghai county 500

16. Heshe Starch Factory Lingao county 500*

17. Nanfeng Feed Factory Qiongshan county 80,000

18. Qiongzhou Feed Factory Qiongshan county 50,000

19. Huaxin Feed Factory Haikou city 50,000

20. Baoli Feed Factory Wenchang county 10,000

21. Fushan Feed Factory Chengmei county 10,000

22. Yangjiang Feed Factory Qionghai county 10,000

23. Xiangshan Feed Factory Tungchang county 10,000

" see Figure 1

2) *indicates that factory is still processing

402

labor. However, this seems to be a phenomenon applicable to the majority of Chinese

state-run enterprises.

Thus, in Hainan cassava is still an important crop, but cassava has suffered a

downward trend due to inefficient processing facilities and government interest mainly

in rubber, sugarcane and fruit trees. It remains an important crop mainly in the foothills

of mountains in central Hainan, especially in those areas close to starch factories.

2. Pilot Site Selection

The RRA confirmed that the areas of Qifeng town in Baisha county and Hongdao

town in Qiongzhong county are probably the most suitable for the Nippon Foundation

FPR project. When we interviewed the members of production team #1 of Qifeng town,

it became quite clear that due to non-ownership of land and limited availability of labor,

there was very little interest in collaborating with the project. The nearby village of

Kongba seemed to be much more promising. Here, farmers ranked erosion as one of the

top problems. They estimated that on the steep slopes cassava yields decreased by more

than 1500 kg/mu between the first and third crop cycle. In addition, some farmers had

already implemented some "traditional" measures to reduce erosion, i.e. increased

planting density. They also knew that some kind of ridges would decrease soil loss.

However, little was done on this because of labor constraints. In general, one family

only has 0.1-0.2 ha land for planting cassava in China; however, in some villages (such

as Kongba) of Baisha county, every family used more than one ha land for cassava

production. In this area cassava is usually planted in monoculture on hill-sides in the

mountainous areas by small farmers, and soil erosion is very serious. After more

detailed RRAs were conducted in these areas, Kongba village and Hongdao town were

finally identified to be the most suitable pilot sites for the FPR project.

3. Demonstration Plots at CATAS

Based on the actual cassava situation in Hainan and our previous research

experience, 17 treatments on erosion control practices were selected and installed in

demonstration plots with 5-10% slope at CATAS. Along the bottom end of each plot

was a plastic-covered channel to collect the soil that washed down the slope with the

runoff water. By weighing these sediments, the amount of erosion in each plot could be

estimated.

4. Farmers' Field Days at CATAS

A farmers' field day/workshop was organized at CATAS from Jan 10 to 12,

1995. About 20 farmers participated; they had been selected from the two pilot sites by

officials from the Agricultural Bureau or by extension agents.

After explaining the objectives and some of the proposed activities of the

403

projects, farmers were taken to see the demonstration plots as well as all the trials of the

cassava program at CATAS. Researchers explained the advantages and disadvantages

of the various treatments in the demonstration plots. The soil that had eroded into the

channels had already been removed and weighed, so farmers could not see in the field

the difference among treatments in terms of soil erosion. But, they could harvest two

varieties in each plot, and thus observe the characteristics of the new variety SCI 24, as

compared to the local variety SC205. The results of the demonstration plots (Table 6)

were presented to the farmers during the discussion session; unfortunately, the results

were rather unusual due to various problems, such as poor germination and damage by

herbicides. During the discussion session, farmers voted on each management option to

select those that they were most interested in. Mr. Xie Dahe, who worked at the Agric.

Bureau of Qiongzhong county, and Mr. Zhou Shao Xiong from the extension station of

Qifeng town of Baisha county, were appointed to be the local coordinators for the

project. Farmers seemed to be most interested in the new varieties and in fertilizer

application.

5. Farmer Participatory Research (FPR) Trials in the Pilot Sites.

As a follow-up to the field day/workshop for farmers at CATAS, demonstration

plots were then established in the farmer's own fields by each of the coordinators at the

pilot sites in March-April of 1995. CATAS provided technical guidance and supplied the

basic planting materials. A total of 52 farmers collaborated in the project, 43 in Kongba

village in Qifeng town of Baisha county, and nine in Hongdao town of Qiongzhong

county. Of these, 44 farmers conducted FPR variety trials with a total of 20 cassava

clones/varieties; 24 farmers implemented soil erosion trials with a total of eight

treatments; and 1 1 farmers conducted fertilizer trials with nine treatments. In the FPR

erosion trials each farmer had only two treatments, a "traditional" practice and an

"improved" practice. Plastic-covered ditches were installed below each plot to determine

erosion. The number of farmers who wanted to participate was much higher than

expected, but we did not want to refuse those farmers that wanted to collaborate in the

project. The large number of participants did cause some problems.

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6. Field Days at Kongba Village

To assess the farmers' opinions about the various treatments in the FPR trials,

a preliminary field day was organized at Kongba village in October 1995 when cassava

was only eight months old. Because farmers did not want to harvest these young plants

yet, we mainly conducted an evaluation of cassava clones/varieties, which had been

planted in the extension station's experimental field. More than 40 farmers (including

some women farmers) participated in this activity. Five plants of each variety were

pulled out and taken to be lined up at an empty field for evaluation. The result of the

farmers' evaluation (Table 7) indicate that farmers were mainly interested in cassava

yield and wind resistance rather than in other characteristics, such as starch content.

Table 7. Varietal characteristics considered of importance by farmers in

Kongba village, Baisha county, Hainan, China.

Character Total score

Fresh root yield 420

Starch content 40

Plant type 15

Ease of harvest 5

Typhoon tolerance 135

Number of roots 105

Plant height 25

Branching" 150

Sweetness of roots2) 0

Color of roots 0

Weight of each root 5

" Prefer some but not excessive branching; no branching gives low yield.

2) Bitter varieties are always preferred over sweet ones, because they are

considered higher yielding; if they had the same yield, sweet vareties would

be preferred.

Another field day was organized during the final harvest in Jan, 1996. This time,

farmers and researchers pulled out ten plants in each plot and weighed the fresh roots to

determine the yield. Varieties were again evaluated by the farmers for various

characteristics. The results of the trials were quickly calculated and were then discussed

with the farmers to select those that were most suitable for the region. These would be

included in the next year's trials.

Table 8 shows the results of the FPR erosion control trials. Most farmers had

not determined the yields of hedgerow barrier crops, but did determine those of

intercrops. The total value of the harvested cassava and that of the intercrops was usually

406

higher than those of other treatments without intercrops. The intercropping with peanut

produced high total income as well as a low level of erosion, which convinced farmers

that this was a good practice. Farmers also showed interest in continuing

experimentation on intercropping with maize and would like to try intercropping with

sweet potato.

Table 9 shows the results of the six FPR fertilizer trials. As soils are quite

fertile in this area, there was no response to any of the nutrients applied, nor to

application of farm yard manure (FYM). Actually, not applying any fertilizers produced

the highest net income. Only in the case of Mr. Tan Ya Zhui, whose land had been

cultivated continously for many years, was there any significant response to fertilizer or

FYM application; the response was mainly to application of P as the soil P-level in his

field was below the critical level of 4-5 ppm P (see soil analyses Table 9).

The results of the 15 FPR variety trials are shown in Table 10. Yields were very

high, averaging about 36 t/ha, both for the improved varieties and the local variety

SC205. Only the clones ZM9057 and OMR33-10-4 produced significantly higher yields

than the local check variety. Both these clones had earlier been selected by farmers for

their high yield and wind resistance.

7. Demonstration and FPR Trials at CATAS and at Pilot Sites in 1996

Since the demonstration and most FPR trials in Qiongzhong county had failed in

1995, it was decided to change this second pilot site to Tunchang county, where farmers

pay more attention to cassava production, while the local cassava starch factory has

shown great enthusiasm to participate in the FPR project.

In Kongba village six farmers will continue to conduct erosion control trials (each

with five treatments), four will do variety trials (each with 4-5 clones) and five will

continue with fertilizer trials (each with ten treatments).

In CATAS a new demonstration plot with 17 treatments was installed to show

farmers a range of new management options.

MAJOR PROBLEMS AND CONSTRAINTS

1. Little attention has been paid to soil erosion problems by officials of local

governments. In some cases they talk well but do little.

2. In the first year, too many participants in Kongba village caused too many problems;

some just wanted to get paid for their participation.

3. It is difficult to find a good local coordinator, who is willing and able to spend a lot

of time working with the farmers. The two coordinators did not always conduct the trials

at the pilot sites as we had requested.

4. Up to now, except for new varieties, no new technologies could really produce an

obvious impact in the demonstration plots. This means that the results of our

demonstration were not very convincing to the farmers.

407

5. It is a lot easier to release new varieties than to transfer new technologies of soil and

water conservation to farmers. However, the supply of planting materials of new

varieties could not meet the local demand, which also caused frustration with the farmers.

SUGGESTIONS AND COMMENTS

1. Most farmers nowadays don't believe something just because we say so; farmers have

to see with their own eyes the good results of new technologies. Therefore, we have to

take advantage of our past experience with farmers and try to make the recommended

practices also more profitable so as to stimulate farmers to adopt these new technologies.

2. It is very important and neccessary to convince officials of the local governments to

support and help our work. We have to let them know clearly about the importance and

the objectives of our FPR project.

3. Transfer of new technologies of soil and water conservation should be combined with

the release of new varieties. In order to release new varieties quickly, there are two

important things that should be considered first: one is to establish some multiplication

fields, using rapid and simple propagation methods in order to produce a large amount

of planting material; another is to set up some representative demonstration sites for

training of extension officials and farmers, to teach them new ways to propagate cassava

planting material. Presently, the multiple shoot system developed at CIAT is being tried

at CATAS.

4. It seems to be realistic to train one local farmer to be the local coordinator of the FPR

participants, and to function also as a contact between researchers and farmers. Because

he knows the local situation clearly, he can inform us better about farmer's needs and

preferences.

5. Researchers should participate more directly in the planning, laying-out, planting,

collecting of eroded sediments, and the harvesting of intercrops. In addition, the FPR

trials should be standardized as much as possible in order to allow for better comparisons

between treatments.

CONCLUSIONS

Up to now, although there have been many problems and constraints, we have

obtained some good results and gained a lot of experience from our FPR project in the

first year. To further succeed, we need to explain more clearly the objectives of our

project and seek the government.s support and help, in order to achieve a wider adoption

of results by participating as well as non-participating farmers.

408

REFERENCES

CIAT International, Volume 14 No. 2 Sept. 1995. ISSN 0120-4084.

Henry G. 1994. Importance of the user perspective in agricultural research. Sasakawa Project

FPR Workshop, held July 24-30, 1994, in Rayong, Thailand.

Henry G. and A. Hernandez. 1994. FPR case study, cassava varietal selection in Colombia.s north

coast. Sasakawa Project FPR Workshop, held July 24-30, 1994, in Rayong, Thailand.

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Table 10. Combined results of 15 FPR cassava variety trials conducted in

Kongba village, Qifeng town of Baisha county in Hainan, China

in 1995/1996.

Varieties/Clones Farmer's name Improved variety Check (SC205)

SC8013 Fu Yong Chuan 40.6 29.7

Tan Yin Chai 36.7 37.5

Tan Ya Zhui 29.7 37.7

Tan Huan Chong 35.7 37.7

Tan Ya-e 36.1 30.5

Zhou Shao Xiong" 35.9 42.9

Average 35.8 36.0

SC8002 Ma Guo Lei 28.4 32.7

Tan Jing Zhou 28.5 38.4

Tan Ya Zhui 24.9 37.7


Average 33.1 37.9

ZM9038 Tan Jing Zhou 26.7 38.4

Tan Ya Lao 42.8 31.2

Average 34.7 34.8

ZM9036 Liu Ya Chun 44.4 33.3

ZM9057 Fu Jin Yu 28.5 32.6

Tang Ya Han 46.0 24.1


Average 42.5 33.2

ZM9066 Tan Yin Chai 32.1 37.5

ZM8639 Tan Ya Qing 34.9 28.8


Average 34.6 35.8

ZM8641 Tan Jia Chai 24.9 28.8


Average 33.5 35.8

OMR33-10-4 Tan Wen Fu 36.3 23.4


Average 44.7 33.1

SCI 24 Tan Yin Chai 50.4 27.7


Average 39.2 35.3

ZM9045 Zhou Shao Xiong" 34.3 42.9



SM 1592-3 Zhou Shao Xiong" 32.0 42.9


"These data maybe overestimated due to unclear spacing.

412

FARMER PARTICIPATORY RESEARCH IN SOIL MANAGEMENT AND

VARIETAL SELECTION IN THAILAND

V. Vongkasem1, K. Klakhaeng1, S. Hemvijit1, A. Tongglum2, S. Katong2

and D. Suparhan2

ABSTRACT

A pilot project on the use of Farmer Participatory Research (FPR) methodologies with

the objective of enhancing farmer adoption of practices that minimize soil erosion in cassava-based

cropping systems, was conducted jointly by DOA and DOAE with technical and financial support

from CIAT in two sites in Nakhon Ratchasima and Sra Kaew provinces. The activities involved

a preliminary survey using RRA methodologies, the setting out of demonstration plots, as well as

farmers meetings and farmers field trips to observe the demonstration plots. The activities also

included conducting various types of FPR trials with farmers on their own land and organizing

a farmer's field day to harvest these trials, to discuss the results, and to select the best treatments

for next-year's trials.

The results revealed that the highest yield of cassava in Soeng Saang district of Nakhorn

Ratchasima province was obtained from planting contour barriers of vetiver grass within cassava

plots; this practice also resulted in the lowest level of soil erosion. On the contrary, in Wang

Nam Yen district of Sra Kaew province, the highest cassava yield was obtained in plots with up-

and-down ridging, while the lowest level of soil erosion was observed with contour ridging.

However, from the discussion between participating farmers and FPR team members it was

concluded that the planting of contour barriers of vetiver grass was the most effective method to

reduce erosion in the long-term, even though this treatment neither had produced the highest yield

of cassava nor the highest income.

Within the same pilot project, FPR trials on cassava varieties and on rates of fertilizer

application were conducted in order to motivate farmers to participate m the project. In Wang

Nam Yen district, Rayong 90 had the highest yield and ranked second in starch content, while

Rayong S had the second highest yield but the highest starch content. In Soeng Saang district,

Rayong 90 ranked first in yield and starch content, while Kasetsart 50 ranked second in both yield

and starch content. With respect to the fertilizer trials, it was found that in Soeng Saang district

the application of 156 kg/ha of 15-15-15 resulted in both the highest yield of cassava and highest

net income.

INTRODUCTION

Cassava is an important cash crop in Thailand. Due to its favorable

characteristics, such as relative ease of cultivation, drought tolerance and adaptation to

poor soils, casava has become very popular, especially for poor farmers. During the past

five years (1990-1994) the total planted area of cassava in Thailand ranged from 1 .40 to

1.52 million hectares. The annual production of fresh roots was 19.0-20.7 million tons,

while the value of exports of dry cassava products was more than 18 billion baht (US $

2

Dept. of Agricultural Extension (DOAE), Rice and Field Crops Promotion Division,

Chatuchak, Bangkok, Thailand.

Dept. of Agriculture (DOA), Rayong Field Crops Research Center, Huay Pong, Rayong,

Thailand.

413

720 million) per year (Office of Agricultural Economics, 1995). The major cassava

growing areas have spread mainly to the poor-soil and drought-prone areas in the

northeastern and eastern parts of Thailand.

Despite the poor soil and droughty conditions in these areas, cassava grows fairly

well. However, when cassava is grown on slopy land soil erosion may be serious even

in areas with gentle slopes of less than 10%. Moreover, in an intensive four-year study

it was shown that soil erosion caused by cassava cultivation was about twice as high as

that caused by cultivation of mungbean, and three times as high as that caused by maize,

sorghum or groundnut (Puttacharoen, 1992).

Due to the wide spacing used in planting cassava and its rather slow early growth

during the first three months after planting, a lot of the soil surface remains exposed to

the direct impact of fallen rain, causing severe soil erosion. Therefore, the Dept. of

Agriculture (DOA), Kasetsart University and the Centro Internacional de Agricultura

Tropical (CIAT) have conducted collaborative research into practical ways to decrease

erosion in cassava production areas. The research showed that there were many ways

to manage or improve cassava cropping systems that will enhance nutrient conservation

and reduce erosion. Each management practice has its advantages and disadvantages: for

example, some practices that control erosion require more money or more management,

while the yield or income does not necessarily increase. The researchers did not know

whether farmers would adopt these practices or not. Therefore, CIAT initiated

collaboration with the Dept. of Agricultural Extension (DOAE) and DOA to establish a

cassava-based cropping system management project and work with cassava farmers in the

provinces, using a farmer participatory research approach. The objective of this project

is to enhance farmers' awareness of the importance of soil conservation, to demonstrate

a wide range of soil erosion control practices, to let farmers select the most appropriate

ones and test these methods on their own fields, so they will develop the most useful

practices for their own conditions. This in turn is likely to enhance adoption and the

continued use of these practices even after the project is finished.

FARMER PARTICIPATORY RESEARCH (FPR) ON CASSAVA SOIL

MANAGEMENT

Objective

To enhance the development and adoption by farmers of improved cassava

cropping systems and cultural practices that will maintain soil productivity and reduce

erosion while sustaining a reasonable farm income.

Location of the study

1. Soeng Saang district of Nakhon Ratchasima province in the lower Northeast.

2. Wang Nam Yen district of Sra Kaew province in the eastern part of Thailand.

414

Responsible organizations

1 . Rayong Field Crops Research Center of the Field Crops Research Institute of the

Dept. of Agriculture (DOA).

2. Field Crops Sub-Division, Rice and Field Crops Promotion Division, Dept. of

Agricultural Extension (DOAE).

3. Centro Internacional de Agricultura Tropical (CIAT).

4. Thai Tapioca Development Institute (TTDI) Research and Training Center in Nakhon

Ratchasima province.

Plan of Implementation

1. To select appropriate areas and within those select the most suitable pilot sites.

2. To collect information on the agro- and socio-economic conditions of cassava farmers

in the pilot sites.

3. To develop a plan of action together with research/extension staff and farmers in

group meetings in the selected pilot sites.

4. To establish demonstration plots in Pluak Daeng, Rayong province (1st year), and at

the TTDI Research and Training Center in Nakhon Ratchasima (2nd year).

5. To provide training for participating farmers and let farmers select the most useful

treatments in the demonstration plots:

6. To let farmers select treatments and implement farmer participatory research trials on

soil erosion control, fertilization and varieties on their own fields in the two pilot

sites.

7. To organize a study tour for participating farmers to the TTDI Research and Training

Center to see and discuss alternative management practices.

8. To jointly harvest the trials and present and discuss the results during a farmers'

field day in order to select best-bet treatments for next year's trials.

Procedure

1. Appropriate Area Exploration and Selection

The criteria for the selection of appropriate areas are: 1 . cassava is an important

crop in the area, both at present and in the future; and 2. cassava is planted on slopes

with serious soil erosion problems. The first step in the process was area exploration.

Three provinces, namely Rayong, Nakhon Ratchasima and Sra Kaew, were explored by

conducting preliminary rapid rural appraisals (RRA). The most suitable pilot sites were

selected by analyzing the RRA results. It was found that in Rayong province most

farmers favored the planting of rubber and fruit trees as the main crop and cassava only

as an intercrop. Thus, the cassava growing area there is likely to decrease. After this

initial exploration, only two locations, i.e. Soeng Saang district in Nakhon Ratchasima

province and Wang Nam Yen district of Sra Kaew province were selected.

415

2. Exploration ofAgro- and Socio-economic Conditions ofFarmer in the two Pilot Sites

A Rapid Rural Appraisal (RRA) technique was used to select the pilot sites, to

ensure that the selected locations are indeed suitable for this project, and to collect

baseline information about the socio-economic conditions and the agricultural practices

used at the onset of the project. The results of these RRAs are summarized in Tables

1-13.

3. Group Meetings with Farmers

Farmers' meetings were held in the two selected pilot sites, i.e. Wang Sombuun

village in Wang Nam Yen district and Noon Sombuun village of Soeng Saang district,

to discuss the objectives, principles and procedures of the project with the farmers, local

extension staff and village leaders. The farmers analyzed and decided for themselves

whether they wanted to participate in the project.

4. Demonstration Plots at the Research Center

Demonstration plots were established along contour lines by cassava researchers

to show farmers a wide range of management practices to help reduce soil erosion in

cassava fields. These demonstration plots were established in two locations, one in

1994/95 in Pluak Daeng, Rayong province, and the other in 1995/96 at the TTDI

Research and Training Center in Huay Bong of Nakhon Ratchasima province.

Unfortunately, some demonstration plots in Pluak Daeng were lost due to flooding.

There were 24 treatments in the demonstration plots, such as the growing of peanut,

mungbean, soybean, sesame, pumpkin and sweet corn as intercrops in cassava. Also

included were contour barriers or hedgerows of vetiver grass, lemon grass, citronella

grass, sugarcane, ruzie grass (Brachiaria ruziziensis), mulberry and king grass; as well

as practices like the application of grass mulch, planting cassava at closer spacing, on

contour ridges, and the use of chemical fertilizers and/or chicken manure or various

green manuring practices. Soil lost due to erosion collected in plastic-covered channels

dug along the lower side of each plot. These sediments were weighed twice during the

cropping cycle and a sample was taken to the laboratory and dried to calculate the

amount of dry soil lost in each treatment. The amount of sediments in the channel of

each plot was a clear demonstration to the farmers about the quantities of soil lost by

erosion due to each treatment. Results of these FPR demonstration plots are shown in

Tables 14 and 15. It is clear that each treatment had a different effect on cassava yield

and on erosion. These demonstrations plot in two locations provided farmers with

examples or alternatives for them to select some methods that may be useful in their own

fields and under their own conditions.

416

Table 1. Secondary data of Soeng Saang district of Nakorn Ratchasima, Baan Khai district

of Rayong and Wang Nam Yen district of Sra Kaew provinces in Thailand in

1994.

District Soeng Saang Baan Khai Wang Nam Yen

Province Nakorn Ratchasima Rayong Sra Kaew

Latitude (°N) 14° 20.N 12° 40.N 13° 40. N

Altitude (masl) -100 -400 -300

Rainfall (mm/yr) 948 -1400 1404

Rainy season ( > 60mm) April-Oct. April-Oct. April-Nov.

Soils loamy Paleustults loamy Paleustults clayey Haplustults

dark brown orwhite sandy loams white sandy loams

red or black clay loams red clay soils

with many rocks

Landscape rolling rolling hilly

- cassava on long gentle slopes on long gentle on short steep

slopes (upper part) (10-20%) slopes

- sugarcane lower part of slope

- rubber lower part of slope

Main cropsfraiV

- cassava 122,200 63,259

- rubber 190 •

- pineapple -

- sugarcane 11,900 57,090

- maize 10,000 116,370

- rice 39,234 38,341

- soybean - 83,215

- fruit trees 15,651 -

- cotton - 13,238

- sunflower - 5,911

- mungbean - 10,290

- sorghum - 3,722

Yield (t/rai)

- cassava 2.7 2.5-5.0 2.65

- sugarcane 10 8.25

- maize 0.5 0.70

- rice 0.5 0.41

- soybean - 0.26

- mungbean - 0.11

Farm size (rai/fam.)

Total 25-150 20-140

- cassava 15-20 10-60

- sugarcane 30 36

- rubber 20 -

- maize 10-15 10-80

- rice - 12

Land ownership presently STK

next year SPK 4-0 12)

presently STK

" 1 ha = 6.25 rai

in future SPK 4-01

2) maximum 100 rai per family

417

Table 2. Cropping systems, cassava varieties and agronomic practices in various subdistricts

of Nakorn Ratchasima, Rayong and Sra Kaew provinces of Thailand in 1994.

Subdistrict Noon Sombuun Baang But Wang Sombuun



Cropping Systems ° C monocrop on C monocrop on C monocrop on

gentle slopes gentle slopes gentle slopes,

C between rubber rotated with M-Mu

Varieties R60, Rl, R3 Rl, R3, R60, R90 R60, R3, R90

Yield (t/rai)2' 2.5-4.0 2.5-5.0 2-4

Land preparation tractor + 3 disc (lx) tractor + 7 disc (2x) tractor + 3 disc (lx)

no ridge or ridge-up ridge with tractor ridge with tractor

Planting method

with weeding contour or up-down mainly up-down

slope

stake size (cm) 15-20 15-20 15-20

stake position vertical vertical vertical

spacing (cm) 70x50 to 120x100 90x60

5-6 C rows

between rubber

Fertillizer use none to cassava

- manure (t/rai) some -

- 15-15-15 (kg/rai) 12-50 at 2 MAP - to maize or soybean

- 13-13-21 (kg/rai) - 50 at 1-2 MAP3'

Weeding - first hoe or Gramoxone hand, 1-2 MAP3' Pre-emerg. herb.

- second hoe or hand tractor Gramoxone hoe

- third Gramoxone or knife Gramoxone

Time of planting

- cassava - first crop March-May (red soil) April April

- second crop Oct-Nov (white soil) June -

- sugarcane March-May March-May -

- maize - - May-June

Time of harvest

- cassava - first crop Dec-Febr - Nov-Febr

- second crop Sept-Dec - -

- sugarcane Dec-Febr Dec-Febr -

- maize - - Aug

Method of harvest by hand or tool by hand or tool tractor + blade

" C = cassava, M = maize, Mu = mungbean

2) 1 ha = 6.25 rai

3> after first weeding

418

Table 3. Cassava utilization and socio-economics in various villages of Nakorn

Ratchasima,Rayong and Sra Kaew provinces of Thailand in 1994.

Subdistrict Noon Sombuun Baang But Wang Sombuun



Cassava utilization (%)

- chipping floor 10-50 in dry season 100

- starch factory 50-90 in wet season 0

Prices

- fresh roots (B/kg) " 1.25-1.50 0.9 1.10-1.15

- dry chips (B/kg) 2.80- -

- 15-15-15 fert. (B/50 kg) 285 280 -

- 13-13-21 fert. (B/50 kg) - 290 -

- urea (B/50 kg) - - -

- Grammoxone (B/5 liters) - 470 -

- pre-emerg. herbicide (B/rai) - - 55

- labor (B/day) 70 80 -

Costs (B/rai)

-land preparation- plowing 100 110 100-120

- discing - 70 80-90

- ridging - 90 80-100

-planting 70-100 90-100 80-100

-fertilization 85-315 350 0-185

-weeding 400-500 4002602l-760

-harvest3 250-400 300-600 440-600

-transport4 150-600 325-650 210-240

Total 1,055-2,015 1,645-2,370 1,150-2,075

Gross income (B/rai) 3,125-6,000 2,250-4,500 3,600-4,200

Net income (B/rai) 1,485-4,625 505,2,300 1,525-4,200

" Root prices Dec.94 Aug .94 Jan'94

27 own labor not included

3/ Harvest cost (B/ton) 100 120 150

47 Transport cost (B/ton)

- to local chipping floor 50-100 100 70-80

- to starch factory 130-150 130 160

419

Table 4. Topography, soils, crops and cropping systems in various villages of Noon Sombuun

subdistrict, Soeng Saang district, Nakorn Ratchasima province of Thailand in 1994.

Village: #1 and 2 U #10

Topography gentle slopes gentle slopes rolling with some

with some hills steep slopes

Soil tvpes black soil white soil (low fert.) red soil (100%)

red soil red soil (fertile)

white soil (s.c.l.)" black soil (fertile)

Land use 2)

some laterite no stones some big stones

- red soil C, Sc, M ,Pa, Ch, F C, M, Veg, Sp, F C, F

- white soil C, Sc, Wm, Pu C

- black soil Veg, Pu

- lowlands nce

- irrigated land Pa Pa, Ta

Crop choices SC mainly by rich Many crops to spread Ta or Pa

farmers income over year in irrig areas

Pa in irrig. areas Rice in lowlands Too dry for M

cotton .soybean

Livestock Few have cattle.pigs Few have cattle,

water buffaloes,

pigs, chickens,

ducks, fish

somme have cattlt

Off-farm activities sericulture none none

Cassava vield(t/rai)

- initially or now with fert. 4-5 4-5

- now with little/no fert. 2-3 2.5-3


- to local chipping floors mainly poor mainly poor 10-20

- to starch factory in Korat mainly rich mainly rich 80-90

1)

s.c.l. = sandy clay loam

2) C = cassava, M = maize, Sc = sugarcane,

F = fruit trees (banana, tamarind, mango, papaya),

Ta = tamarind, Pa = papaya, Sp = sweet potato, Ch = chili peper, Pu = pumpkin,

Wm = watermelon, Veg = vegetables

420

Table 5. Cassava cropping systems, varieties and agronomic practices in various villages of

Noon Sombuun subdistrict, Soeng Saang district, Nakorn Ratchasima province of

Thailand in 1994.

Village: #1 and 2 H #10

Cropping systems C monoculture

continuous cropping

C monoculture

sometimes rot. M

C monoculture

continuous cropping

Varieties R60, Rl, R3, R5

Pumpuang

R60, Rl, R3, R90

R5, KU-50, CMC

Pumpuang

R60 (80%), R3

R90, KU-50, R5

Red Rayong, Red KU

Land preparation tractor +3disc (lx)

no ridging

tractor +3disc (lx)

no ridging

tractor +3disc (lx)

no ridging

Planting method

-stake position

-spacing (cm)

vertical vertical vertical

70x50 (white soil)

Fertilization (kp/rai)

120x100 (red soil) 120x100 (red soil)

-15-15-15 12-25 25-50 (white soil)

sometimes

25

sometimes-manure

Weeding

-first

-second

-third

hoe

hoe

hoe

hoe or Gramoxone

hoe or hand tractor

knife

hoe

Gramoxone

Time of planting

-first crop

-second crop

knife

Time of harvest

-first crop

-second crop

March

Nov

Febr-Apr (red soil)

Oct-Nov (white soil)

March-Apr

Dec

Aug

Dec-March

Sept-Dec

Jan-Febr

421

Table 6. Principal cassava varieties and their characteristics in several villages of Noon

Sombuun subdistrict, Soeng Saang district, Nakorn Ratchasima province of

Thailand in 1994.

Village: U 1 and 2 #4 #10

Main varieties

Secondary varieties

R60, Rl, R3

R90, R5

R60, Rl, R3

R90, R5

R60, R3, Rl

R90, R5

Characteristics

Rayong 1 Drought tolerant

Low yield

Low starch

Rayong 60 High yield

Low starch

Good plant type

Convenient-

weeding

High yield

Low starch

Susc. root rots

Good in white

and red soil

High yield

Low starch

Drought tolerant

Rayong 3 High yield

(esp. 1st yr)

High starch

Short stature

High starch High yield

High starch

Low germination

after storage

Difficult harvest

Rayong 90 Only good yield

in white soil

High starch

High yield

High starch

Difficult weeding

Low germination

after storage

Rayong 5 High yield

High starch

Drought tolerant

422

Table 7. Main problems and farmer solutions in several villages of Noon Sombuun

subdistrict, Soeng Saang district, Nakorn Ratchasima province of Thailand in

December 1994.

Problems Solutions

Village #1 and 2

Village #4

1) Low price (except this year)

2) Lack of labor

3) Decreasing yields (20 % in second yr)

4) Root rots (7-14% yield loss)

1) Erosion (5-10% yield loss)

2) Root rot in white soil

during last 2 years (esp.in R60)

3) Spider mites (esp.in red soil, R60)

4) Decreasing yields

Need cassava harvester

Increasing use of fertilizer

Lemon grass barriers

Fill gulleys back in

Plant bamboo in higher

areas

Need to apply fertilizers

after 4-5 years

Village #10 1) Drought (25% yield loss)

2) Erosion (14% yield loss)

3) Spider mites (50% yield

loss in some areas)

4) Lack of labor (esp.for harvest)

Plant vetiver grass

Plant on contour ridges

(but break with heavy rain)

Tamarind + ruzie grass

in contour strips

Use cassava harvester

423

Table 8. Cassava processing in Soeng Saang district and in Korat city of Nakorn Ratchasima

province of Thailand in December 1994.

Soeng Saang district Korat city

Manufacturer

Ownership

Products

Production capacity

Tirapong Chipping Factory

private

cassava chips

2.56 ha drying floor

Actual production (t/year) about 3,000 chips

Production period 5 months (Oct-Febr)

Raw mat. needs (t fresh roots/year)

Price fresh roots (B/kg) 1 .0 - 1.35-1.40"

Price products (B/kg)

Conversion ratio

Starch content determ.

Technology

By products/waste

2.80 chips

2.0-2.4 fresh roots = 1 chips

by variety and break roots

chipped roots spread,

turned over, dried in 3 days

Raw material cost/total cost 95-100

Sa-Nguan Wongse Industries Co.

private

raw starch

modified starch

glucose (next year)

185,000 starch

(largest in Thailand)

140,000 starch

6,000-12,000 mod. starch

year-round, 24 hrs/day

875,000

-» 1.58 (at 30% starch)

5 fresh roots =1 starch

measure starch content

washed roots grated, centrifuged

flash-dried

1) Waste fiber (50-58% starch)

pressed, dried, used in

pellets or chicken feed

2) Peel sold as compost or for

mushroom production (B300/t)

3) Waste water sedimented,-*

irrigate eucalyptus plantation

85-88

"plus B 0.02/kg for truck driver

424

Table 9. Topography, soils,

subdistrict, Wang

crops and cropping systems in two villages of Wang Sombuun

Nam Yen district, Sra Kaew province of Thailand in 1995.

Village #5 Village #3

Topography

Soil types

Land use

Crop choices

Livestock

Off-farm activities

Cassava yield


-chipping floor (mainly

for sale to starch factory)

-starch factory

(>100km)

rolling, foothills

reddish-brown clay loam

many brown/purple stones

high areas: cassava or

cassava rotated with

maize and soybean

low areas: cassava,

maize, soybean, mungbean,

cotton, sunflower,

eggplant, custard apple,

banana, cucumber, mango

1. maize

2. cassava

3. soybean/mungbean/sunflower

chickens, water buffalo

beef cattle, fish

part-time work

mainly in construction

Rayong 1: 2-3 t/rai

Rayong 60: 3-4 t/rai


99

1

rolling, foothills

brown/purple stones

big rocks on 30 % of area

cassava rotated with

maize and soybean

1. maize

2. cassava

3. mango

chicken, beef cattle

part-time work

Rayong 3: 2-3 t/rai


Red Tip: 2-3 t/rai

100

0

425

Table 10. Cassava cropping systems, varieties and agronomic practices in two villages of

Wang Sombuun subdistrict, Wang Nam Yen district, Sra Kaew province of

Thailand in January 1995.


Cropping systems

Varieties

Land preparation

Planting method

-stake position

-spacing (cm)

Fertilization (kg/rai)


rotated with maize

and soybean

R90>R3>R60>R1

tractor +3disc (2x)

tractor + 7disc (lx)

ridging (mostly

up-down slope)

vertical or inclined

R60 at 50x100

R90 at 50x75 or 50-60x100

Rl at 100x100

no fertilizer to cassava

or 6-20 of 15-15-15

at 3 MAP


rotated with maize

and soybean

R60>RedTip>R3>R90

tractor + 3disc (lx)

ridging

vertical or inclined

R90 at 50-60x100

20 of 15-15-15,

13-13-21 or 25-7-7

Weed control 1) Alachlor, Diuron as pre-emerg. 1) Alachlor as pre-emerg.

2) Gramoxone as post emerg. 2) Gramoxone as post emerg.

3) hoe 3) hoe or knife

Harvest by tractor + harvester

manual lifting and loading

Time of planting Apr-May Apr-May

Time of harvest Dec-Jan Nov-Jan

426

Table 11. Principal cassava varieties and their characteristics as well as the main problems

mentioned by farmers in two villages in Wang Sombuun subdistrict, Wang Nam

Yen district, Sra Kaew province of Thailand in January 1995.

Village Village #5 Village #3

Main varieties

Characteristics

-Rayong 1

-Rayong 3

-Rayong 60

-Rayong 90

R90, R3, R60, Rl

low yield

yields are decreasing

high yield, low starch,

good weed control,

not always accepted by

starch factory

high yield, high starch

good weed control

R60, Red Tip, R3, R90

high yield, high starch,

small plant

high yield, good soil cover

good price, decreasing yield

-Red Tip " tall plant, low yield,

good weed control

Problems 1 . low price 1. lack planting material

of good varieties2. irregular rainfall

3. lack of labor 2. lack knowledge about

fertilizers4. lack of capital

5. erosion 3. erosion

6. good varieties difficult

to find and expensive

4. diseases

7. decreasing yields when

planted contiuously

5. lack of labor

427

Table 12. Cassava utilization and socio-economics in two villages in Wang Sombuun

subdistrict, Wang Nam Yen district, Sra Kaew province of Thailand in January

1995.



- chipping floor " 99 100- starch factory v

1 0

Prices

- fresh roots (B/kg) 1.19-1.20 in chipping yard

1.32 in starch factory

- 15-15-15 fert. (B/50 kg) 285

- 13-13-21 fert. (B/50 kg) 300

- urea (B/50 kg) 250

- labor (B/day) 100

Production costs (B/rai)

- land preparation - plowing 100-120 100

- discing 80-90 -

- ridging 80-100 80

- planting 100 80

- weed control

- pre-emergent

- herbicide cost 160 60

- labor 100 40-50

- post emergent

- Gramoxone cost 200 160

- labor 100.3)

- manual control with hoe or knife 200_3)

- fertilization

- fertilizer cost 100 120

- labor 85.3)

- harvest

- digging (by tractor) 150 150

- collecting 300-450 290

- transport 210-240 225

- land rent 400

1,310"

-

Total 1,500-2,195

Gross income (B/rai)3,600-4,20041

3,600"

Net income (B/rai) 1,800-2,700" 2,290"

"most chipping floors do not chip, but transport fresh roots to starch factories

2)starch factories in Kabin Buri or Chanta Buri, both about 100 km away

"own labor not included

4,high gross and net income due to unusually high cassava price

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5. Farmers Training

Farmers from the two pilot sites that were interested in participating in the project

were invited to join a two-day training course at the Rayong Field Crops Research Center

with the objective of: 1 . increasing the farmers' knowledge and understanding of soil and

water conservation in cassava production; 2. to discuss with the farmers how to conduct,

with the help of researchers and the extension workers, FPR trials on their own fields,

and 3. to increase their knowledge on new cassava varieties and production techniques.

Furthermore, they visited the demonstration plots on management practices to reduce

erosion and discussed the advantages and disadvantages of each treatment. Each farmer

was asked to score the various soil erosion control treatments, considering their likely

effect on yield and income, their effectiveness in reducing erosion, and whether they

seem to be useful under the farmer's own conditions in the village. The results of these

farmers' evaluations are also shown in Table 14.

6. FPR Trials on Soil Erosion Control, Varieties and Fertilizer Use

After the training session and farmers' evaluation of the demonstration plots,

researchers from DOA, together with extension workers from DOAE, discussed with

collaborating farmers in the pilot sites the type of FPR trials that they wanted to do on

their own land, as well as the treatments to be included, plot size, management etc.

Farmers in Soeng Saang district decided to conduct trials on erosion control, on

fertilization and on cassava varieties, while farmers in Wang Nam Yen district decided

to conduct only trials on erosion control and varieties.

6. 1 Soil erosion control trials

FPR team members and collaborating farmers selected the most appropriate areas

and layed out the FPR erosion control trials for the farmer along contour lines. The

farmers participating in the project discussed and selected the treatments they wanted to

test in their own trials:

- Nine farmers in Soeng Saang chose to do erosion control trials and selected five

treatments, namely 1. their own traditional practice of up-and-down ridging; 2. vetiver

grass contour barriers; 3. contour ridging; 4. sugarcane contour barriers; and 5.

intercropping. However, farmers selected different intercrops: five farmers selected

peanut, one selected sweet corn and one farmer selected mulberry bushes instead of

vetiver grass as contour hedgerows.

6.2 Cassava varieties and fertilizer trials

FPR trials were also conducted on varieties and fertilizer use by those farmers

that wanted to participate but did not have slopy land to conduct erosion control trials.

In the variety trials, five varieties were compared, namely Rayong 1, Rayong 3, Rayong

5, Rayong 60, Rayong 90 and Kasetsart 50.

In the FPR fertilizer trials different combination of N, P and K were applied with

the objective of determining which nutrients produced the greatest benefits at the lowest

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costs. The treatment were as follows:

1. NqPqKo No fertilizer application

2. NjoPoKq 50 kgN/ha as urea

3. N-ioPjoKo 50 kgN/ha as urea and 50 kg P205/ha as triple superphosphate

4. NjoPoKjo 50 kgN/ha as urea and 50 kg K20/ha as potassium chloride

5. N^P^K^ 166 kg/ha of 15-15-15 compound fertilizer

6. NjoPjoK^ 332 kg/ha of 15-15-15 compound fertilizer

In Soeng Saang district three farmers conducted variety trials and five farmers

conducted fertilizer trials. On the other hand, in Wang Nam Yen only varietal trials

were conducted by seven farmers.

7. Study Tour

In 1995/96 demonstration plots with 24 treatments were established at TTDI's

Research and Training Center in Huay Bong of Daan Kun Tod district in Nakhon

Ratchasima province. Therefore, in August 1995 participating farmers from the two pilot

sites and farmers from nearby villages visited the demonstration field. They studied and

compared the advantages and disadvantages of each soil erosion control method and then

scored each treatment in terms of yield potential, effectiveness in erosion control and

general usefulness for their own conditions. Results of the demonstration plots as well

as the farmer's preferences are shown in Table 15.

8. Harvesting Field Day

All FPR trials were harvested at about ten months after planting. The

participating farmers in each pilot site were asked to harvest their trials on the same day

so that the FPR team members could help in determining the yield and starch content in

each treatment. After all harvest data were tabulated they were presented and discussed

with the participating farmers. These data from the various FPR trials were then used

as the basis for developing a plan for the following year.

Results of FPR Trials

1. FPR Erosion Control Trials

Results from the FPR erosion trials in Soeng Saang (Table 16) show that growing

sugarcane as contour hedgerows gave the highest net return of 34,715 baht/ha, while

planting vetiver grass contour barriers was the most effective treatment in reducing soil

erosion. In this treatment only 8.5 t/ha of dry soil was lost due to erosion, while the

highest soil loss of 24.8 t/ha was observed with up-and-down ridging.

Research results from Wang Nam Yen district (Table 17) indicate that mungbean

intercropping produced the highest net return of 30,880 baht/ha (1 ,235 US$/ha), followed

by Ruzie grass contour barriers, which produced 30,300 baht/ha (1,212 US$/ha). Ruzie

grass contour barriers were also very effective in reducing erosion, but it was observed

432

Table 15. Cassava yield, starch content and dry soil loss due to erosion in 24

treatments in demonstration plots at TTDI in Huay Bong, Nakorn

Ratchasima province of Thailand in 1995/96.

Root Dry soil Farmer

yield loss preference

Treatments (t/ha) (t/ha)

1. peanut intercrop8.733)

30.8119d 02)

2. soybean intercrop 17.11 25.14 14 0

3. sesame intercrop 11.72 20.02 1 0

4. pumpkin intercrop 19.62 26.93 21 10

5. vetiver grass barrier 20.32 23.90 11 24

6. sugarcane barrier 19.50 34.07 16 0

7. lemon grass barrier 18.33 26.48 15 20

8. ruzie grass barrier 10.82 19.14 3 11

9. contour ridging 20.61 18.79 24 5

10. mulberry tree barrier11.044)

14.76 7 0

1 1 . citronella grass barrier14.324'

16.81 8 8

12. King grass barrier5.624)

16.43 0 0

13. Crotalaria mulch 15.61 15.66 1 2

14. Canavalia mulch 17.65 11.99 1 2

15. pigeon pea mulch 13.95 14.61 0 0

16. sweet corn intercrop 22.17 18.92 32 4

17. chicken manure 19.26 21.59 28 9

18. fertilizer + manure 23.44 18.66 30 15

19. fertilizer + compost 20.94 13.47 23 6

20. traditional practices 18.33 18.00 15 9

21. up-down ridging 17.15 24.57 3 0

22. closer spacing 19.82 33.59 11 7

23. no fertilizers 19.48 28.46 0 0

24. little fertilizers 15.54 27.06 2 4

"number of farmers from Soeng Saang considering treatment as "good"

2,number of farmers from Wang Nam Yen considering treatment as "good"

3>low yield because of continuous intercrop competition as peanut was not harvested

4)low yield due to excessive shading from hedgerow species

that the seed and stolens of the grass soon spread into the cassava field, thus becoming

a serious weed problem. Vetiver grass contour barriers were only intermediately

effective in reducing erosion (Table 17). Vetiver grass contour barriers were less

effective in reducing erosion in this location because the grass established a solid

hedgerow only gradually, while heavy rains after cassava planting caused rather severe

soil loss due to erosion.

433

After the harvest, the FPR team presented the collected data to the participating

farmers in the two pilot sites. They exchanged opinions and discussed together the

advantages and disadvantages of the different methods for soil erosion control. Farmers

in Soeng Saang indicated that vetiver grass contour barrier had the highest efficiency in

erosion control, followed by contour ridging and sugarcane contour barriers. Later,

farmers had a group meeting and selected the management practices they wanted to test

in the trials in the following year. These include:

1 . the farmer's own practice of up-and-down ridging

2. sweet corn-cassava intercropping

3. squash/pumpkin-cassava intercropping

4. sugarcane contour barriers

5. vetiver grass contour barriers

Similarly, farmers in Wang Nam Yen considered that vetiver grass contour

barriers had the highest efficiency in erosion control. Although the research results did

not show this grass to be particularly effective in erosion control, in some trials the grass

had shown its great potential in reducing soil loss due to erosion. Farmers expected this

method to be the most effective in the long-term. The farmers group of Wang Nam Yen

selected the following treatments for the next year's trials:

1 . the farmer's own practice of up-and-down ridging

2. contour ridging

3. vetiver grass contour barriers

4. mungbean-cassava intercropping

5. dried grass mulch application between cassava rows

2. FPR Variety Trials

In Soeng Saang, the results of the variety trials in which six varieties were

compared, showed that Rayong 90 produced the highest yield of 37.0 t/ha and had the

highest starch content of 29.5%, followed by Kasetsart 50 with a yield of 35.7 t/ha and

starch contant of 28.1% (Table 18).

In Wang Nam Yen, Rayong 90 produced the highest yield (32.5 t/ha). The next

variety was Rayong 5 with slightly less yield (30.7 t/ha). On the other hand, Rayong 5

had the highest starch content (30.3%), while the starch content of Rayong 90 and

Kasetsart 50 were equal (28.7%) (Table 18).

3. FPR Fertilizer Trials

Fertilizer trials were conducted only in Soeng Saang. The results (Table 19)

indicate that the application of 25 kg N, 25 P205 and 25 K:0/ha gave the highest yield

of 31.6 t/ha and also the highest net income of 32,113 baht/ha. This treatment

434

corresponds with an application of 166 kg/ha of 15-15-15 fertilizers, which happens to

be the present fertilizer recommendation.

Constraints

The following constraints were the main cause of problems encountered in the

FPR project:

1 . The local extension workers, who are responsible for this project in the pilot sites, are

often busy with other routine work, so they could not spend much time in this project.

2. Some participating farmers did not take good care of their trials.

3. In some erosion plots there were slopes in two directions causing problems in the

collection of eroded sediments.

4. In the rainy season, the run-off is very heavy and farmers were not always able to

protect their FPR erosion trials from run-off coming from fields above. This damaged

some plots and resulted in excessive erosion in some plots not at all related to

treatments. This reduced the reliability of the erosion data.

FUTURE PLANS

New FPR trials are already being implemented in the same districts to confirm

the results of last year. Some participating farmers who showed little interest in the

project have been replaced by new farmers. In addition, the project has selected some

more suitable areas for the soil erosion control plots.

REFERENCES

Office of Agricultural Economics 1995. Agricultural Statistics of Thailand, Crop Year 1994/95

Ministry of Agriculture and Co-operatives, Bangkok, Thailand.

Puttacharoen, S. 1992. Nutrient Removal by Crop and Nutrient Loss by Erosion in Cassava

in Comparison with that of Other Crops. MSc thesis. Kasetsart Univ., Bangkok, Thailand.

103p.

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Table 18. Results of three FPR variety trials conducted by farmers in Noon Sombuun village

of Soeng Saang district, Nakorn Ratchasima province of Thailand in 1995/96.

Cassava yield (t/ha) Starch content (%)

Rayong Rayong

Farmer s

name 1 3 5 60 90

KU

50 1 3 5 60 90

KU

50

1. Mr. Prasit . - 32.4 36.8 - 31.2 - - 28.9 29.2 - 29.2

2. Mrs. Lek 22.0 9.0 20.5 15.5 20.0 20.0 26.1 25.3 25.9 19.8 29.8 27.9

3. Mrs Chuen 39.0 37.0 43.0 39.0 54.1 56.0 25.7 28.0 23.9 25.9 29.3 27.1

Average 30.5 23.0 32.0 30.4 37.0 35.7 25.9 26.6 26.2 25.0 29.5 28.1

Table 19. Average results of five FPR fertilizer trials conducted by farmers in Noon

Sombuun village of Soeng Saang district, Nakorn Ratchasima province of

Thailand in 1995/96.

Fertilizer rate Root Gross Fertilizer Net

N-P2O5-K2O yield income cost income

(kg/ha) (t/ha) < - - -—(baht/ha) >

0-0-0 28.6 30,030 0 30,030

50-0-0 29.2 30,660 811 29,849

50-50-0 31.0 32,550 1,755 30,795

50-0-50 30.7 32,235 1,261 30,974

25-25-25 31.6 33,180 1,067 32,113

50-50-50 30.8 32,340 2,133 30,207

Prices: cassava fresh roots B 1.05/kg

urea 365/50kg

triple superphosphate 425/50kg

KC1 270/50kg

15-15-15 320/50kg

438

FARMER PARTICIPATORY RESEARCH IN CASSAVA

TECHNOLOGY TRANSFER IN INDIA

S. Ramanathan and M. Anantharaman1

ABSTRACT

The concept and methodology used in the transfer of technology (TOT) have undergone

changes over the years corresponding to farmers' needs, and as a result, farmer participatory TOT

has become more relevant, especially in complex diversified risk-prone (CDR) farming systems.

The TOT in cassava, which largely belongs to the CDR farming system in India, is no exception

to this.

The National Demonstration Programme (NDP) on cassava, which started in 1970, was

the first organized attempt to transfer the improved cassava technologies, especially the hybrid

varieties. The main objective of NDP was to convince the farmers about the production potential

of the new cassava hybrids by conducting demonstrations in farmers' fields by scientists. It

restricted the scope of farmers' participation in technology transfer. Their role was mainly

confined to be the passive spectator of the demonstrations.

The scope of the farmers' participation was widened under the Operational Research

Project (ORP) in the mid-seventies, which laid emphasis on the identification of constraints in the

adoption of technologies. Though the farmers did not have much say in the technology transfer,

they played a significant part in assisting the scientists in identifying the operational constraints

to adopting the cassava technologies. The Lab-to-Land Programme (LLP), launched during 1979,

witnessed greater participation of adopted farmers, by emphasizing direct linkages between

scientists and farmers. The participation of the farmers was ensured right from the benchmark

survey of farm families, the demonstration of cassava technologies, identification of potential

spheres of development, and the dissemination of the impact of the program through fellow

farmers and mass media. The impact assessment of the program revealed that there can not be

a uniform package for transfer, and very often farmers try to blend the new technologies with

their traditional practices. Hence, there is a need to evolve appropriate location-specific

technologies suitable for various micro-environments.

On the realization of this fact, CTCRI has implemented a farmer participatory research

program on cassava technology assessment, refinement and integration, which indicates the

differential pattern of technology preferences in various farming situations.

INTRODUCTION

Cassava is a crop of small and marginal farmers operating under the complex,

diversified and risk prone (CDR) system of agriculture in India. The Central Tuber

Crops Research Institute (CTCRI) is spearheading the research and development of

cassava in the country, together with the extension work being carried out by the

Department of Agriculture/Horticulture of Kerala and Tamil Nadu, the two major cassava

growing states in India. Following the changing trends in the agricultural transfer of

technology (TOT) programs at the national level, the TOT programs of cassava too have

undergone changes at appropriate times, facilitating more and more farmers' participation

in the TOT process over the years.

1 Central Tuber Crops Research Institute (CTCRI), Thiruvananthapuram, Kerala, 695 017,

India.

439

Historical Perspective of TOT in Cassava

During the early seventies (1971-74) National Demonstration (ND) on cassava

was the pioneering attempt to transfer cassava technologies on a large scale, especially

the hybrid varieties in India. This program, the oldest front-line extension project

conceived by the Indian Council for Agricultural Research (ICAR), was implemented by

various ICAR Institutes and Agricultural Universities, but with little direct participation

of farmers, either in technology transfer or in their generation. The farmers' role was

mainly confined to be the passive spectator of the demonstrations (Table 1).

Farmers' participation in cassava technology transfer was first introduced under

the Operational Research Project (ORP) on cassava, implemented during 1976-81 in a

suburb village near Thiruvananthapuram city of Kerala State. Although the beneficiaries

of ORP did not have a say in the technologies of cassava to be transferred, they were the

dominating partners in the identification of socio-economic and technological constraints

in the adoption and spread of introduced cassava technologies envisaged under the ORP.

The scope of farmers' participation in cassava technology transfer was increased

under the Lab-to-Land program (LLP) launched during 1979 to commemorate the Golden

Jubilee celebration of ICAR. Right from the initial benchmark survey of the selected

farm families up to the final impact survey of the program after withdrawal from a

particular village, the beneficiary farmers enthusiastically took part in the TOT of

improved cassava technologies. Occasions such as laying out the demonstration plots,

group meetings, harvest festivals etc. were effectively utilized to enlist the participation

of both the beneficiary as well as non-beneficiary farmers in the technology transfer

process. The sharing of successful experiences in the introduced cassava technologies

by the participating farmers with their fellow farmers through radio, television and the

print media acted as a motivating factor in the further spread of cassava technologies

(Anantharaman and Ramanathan, 1986).

Impact Implications

A study on the impact of LLP on cassava, undertaken across the implemented

villages, revealed a differential pattern amongst the villages (Anantharaman and

Ramanathan, 1996). It was seen that the socio-economic conditions operating at the

micro-level of the farmers played a significant role in influencing the impact of the

program in various villages. Moreover, a complete adoption of the entire package was

not very common; rather, the farmers tended to use a blend of the introduced cassava

technologies and their traditional practices, according to their socio-economic and cultural

conditions. The slow rate of multiplication coupled with the time lag between the

harvesting and subsequent planting continued to pose a severe constraint in the rapid

spread of cassava technologies. The absence of a specialized agency for large-scale

multiplication and distribution of planting material of hybrid cassava further aggravated

this problem. Notwithstanding these bottlenecks, the cassava growers, if they are not

440

innovators, they are also not laggards in adoption; they show a keen interest in the

adoption of improved cassava technologies once they are exposed to those technologies

and backed up with an adequate supply of critical inputs, such as planting material and

fertilizers.

Table 1. Transfer of Technology Projects of cassava in India and the extent of

farmers' participation.

Name of the project Period Impact

Nature and extent of

farmers'participation

National Demonstration 1971-74 An awareness about Very much limited.

Program hybrid cassava Only a spectator of

varieties created. the demonstrations

Operational Research 1976-81 Impressive yield Participation widened.

Project performance and Dominating partner

income generation. in identification of

Constraints in TOT various constraints.

of cassava identified.

Lab-to-Land Program 1979 to Impressive yield Participation from the

today performance and start to the end of the

income generation. program. Experience

Spread of introduced sharing between farmers

varieties. Overall for effective

development of dissemination.

adopted families.

FPR Program in Since Location-specific Active partners in the

cassava 1994 varieties identified. selection and spread of

varieties.

The overall impact of the TOT efforts in cassava clearly indicated the necessity of

generating location-specific technologies, particularly new varieties suitable to various

micro-climatic environments of cassava production zones in the country. On realization

of this fact, and taking into consideration the worldwide recognition for farmers.

441

participation in the development of agricultural technologies and transfer, CTCRI has

initiated during the mid-nineties a program of participatory research in cassava, especially

for varietal evaluation and transfer. Under this program the farmers are given a basket

of cassava varieties from which they can make a choice suitable to their own conditions

and requirements.

FARMER PARTICIPATORY RESEARCH AND TRANSFER IN CASSAVA

Generally, agricultural technologies are developed under ideal conditions and based

on various criteria they are assumed to be solving farmers' problems, as perceived by the

scientists. But, quite often there exists a wide gap between what is perceived as needed

by the scientists and what is actually needed by the farmers. As a result, the majority

of the technologies turn out to be a mismatch and their transfer to the end-users is found

difficult. In this regard, the methodology of farmer participatory research is expected

not only to better identify the topics to be researched, but also to facilitate the effective

transfer of improved technologies. Keeping this in mind, in 1994 a program of farmers'

participation in cassava varietal evaluation and popularization was initiated at CTCRI,

following the methodology developed by Anantharaman et al. (1994).

Methodology of FPR in Cassava

Figure 1 shows the five stages of the FPR methodology used at CTCRI.

Stage I. Selection of villages and diagnosis of the cassava crop status.

As an initial step in the conduct of on-farm trials, a suitable village has to be selected,

i.e. a village where cassava plays a significant role in the economy of the village, and the

selected village should have a major area under cassava. Using these criteria, Anacode

village in Thiruvananthapuram district of Kerala was selected for implementing the FPR

approach. A detailed study on the status of the cassava crop in this selected village was

undertaken using various participatory rapid appraisal (PRA) tools and techniques. These

included:

/. Village transect

The village transect of Anacode represents the cross section of the village, indicating

the topography, soil type, crops grown, livestock raised, irrigation source, problems etc.

(Figure 2). The selected village has a undulating topography like most Kerala villages,

with low-lying paddy fields located at one end of the village and adjoining uplands.

Though traditionally the lowland area is mainly used for paddy cultivation, of late cassava

has emerged as a money-making crop under low-land conditions. A sizable proportion

of the uplands in the village is under cassava, both as a monocrop and intercropped under

either rubber trees during the initial period or, to a lesser extent, under coconut trees.

It is clearly evident from the transect that cassava is an important crop in Anacode, raised

under both upland and lowland conditions.

442

STAGE I Selection of village and diagnosis of crop status

U

STAGE II Selection of farmers and formation of evaluation groups

uSTAGE III Laying out and management of on-farm trials on

cassava varieties and evaluation by various user

groups and scientists

uSTAGE IV Evaluation of selected varieties for validating the performance

uSTAGE V Popularization of the most preferred variety.

Release of the variety for large scale TOT

Figure 1. Schematic representation of the methodology ofFPR used in cassava by CTCRI

in Kerala, India.

443

Lowland Upland

Soil type

Crops

Trees

Irrigation

Resources

Livestock

Drainage

Problem

Clayey

Paddy, Cassava

Banana, Vegetables

Aroids

Canal

Fodder

Medium

Conversion of paddy

land to other crops

Red and laterite

Rubber, Cassava,

Coconut, Yams,

Mango, Jackfruit

Tamarind,

Perumaram etc.

Wells and rainfed

Fuel, Grass,

Cattle and poultry

manure

Cow, Goat,

Buffalo, Poultry

Good

Lack of

irrigation

facilities

Figure 2. Transect ofAnacode village in Trivandrum district of Kerala, India.

444

2. Cropping pattern and seasonality ofpests and diseases

The informal interview with key informants together with a diagramming

technique, cross-checked with the secondary data available at the village Agricultural

Office, revealed that besides paddy, cassava is also grown to a large extent in the

lowland. Normally two crops of cassava are cultivated under this condition, one during

the period April/May to Sept/Oct and another one from Oct/Nov to March/April. The

crop takes about 6-7 months until harvest under the lowland condition. Non-availability

of mosaic-free stems and damage by rats are the two most serious problems experienced

under this condition. In the upland, cassava is planted during April/May and is harvested

in Feb/March. As in the case of the lowlands, cassava mosaic disease is an important

constraint to increasing cassava production in the uplands too. Kariyila poriyan,

Mankozhunthan and Karukannan are the popular cassava varieties grown by the farmers.

The high-yielding cassava variety Sree Vishakom (H-1687) is also being cultivated.

3. Crops ranking

Farmers were also asked to compare the relative importance of the various crops

they grow based on the criteria that they feel are important in choosing a crop enterprise.

Using these criteria, i.e. food security, profitability, low pests and diseases incidence,

tolerance to drought, low input requirement and good marketability, rubber was the most

preferred crop, closely followed by cassava, owing to its drought tolerance, low pests and

disease incidence, low input requirement and food security (Table 2). Banana and

vegetables, though considered as being the most profitable, were susceptible to pests and

diseases and required high inputs for their cultivation.

4. Cassava varieties ranking

A group of farmers was asked to rank their five most popular cassava varieties

against the characters they considered most important, such as yield, taste, starch content,

root compactness and season (Table 3). It is clearly evident from the ranking that none

of the varieties were ranked first in all these aspects, indicating that each of the popular

varieties excelled others in one character or the other. The hybrid cassava variety Sree

Vishakom was ranked first in yield, taste and compactness of roots, but was preferred

last with respect to starch content and season (non-bound). Similarly, the local variety

Monkozhunthan rated first for starch content but was ranked last for taste. However, the

overall ranking revealed that three of the varieties had quite similar scores.

5. Problem-cause relationship in cassava

Problem-cause relationships were determined with a group of farmers for both

lowland and upland conditions. Low productivity of cassava was perceived as the major

problem in both the upland and lowland situations (Figures 3 and 4). The average

productivity of cassava ranged from 15-17 t/ha under upland and 20-25 t/ha under

445

lowland conditions. The bio-physical as well as the socio-economic causes for such low

yields are shown in the Figures. Of the various causes, non-availability of improved

short-duration varieties was found to be the major limiting factor to cassava production

under both production systems. Evaluation and identification of suitable cassava varieties

with farmers' participation contemplated under the FPR program could be the possible

solution to overcome this problem and increase the cassava productivity in Anacode

village.

Stage II. Selection of farmers and formation of evaluation groups

/. Selection of cooperatorfarmers

Two farmers with long experience in cassava cultivation, who were willing and

cooperative in nature and who have a high proportion of their land planted to cassava,

were chosen, one each for conducting an on-farm trial (OFT) under upland and lowland

conditions.

2. Formation of evaluation groups

It was not possible to establish a large number of trials to be used as replications

in the on-farm research, due to the lack of mosaic-free planting material and other

resources. Instead, by forming groups of various evaluator categories, such as farmers,

traders and farm women, to evaluate a single trial, each member of the group was

considered to be a replication/observation for the purpose of analyzing and interpreting

the outcome of the trials. However, care was taken to involve the entire group in the

management of OFT. Accordingly, at the village level a farmers group, a traders group

and a farm women group were formed, consisting of persons with extensive experience

in cassava cultivation or trade, and having the ability and inclination to participate in the

evaluation and to give their assessment on the cassava varieties. In addition, a group of

scientists comprising breeders, agronomists and plant protection specialists, coordinated

by a social scientist, was also formed, in order to determine the degree of agreement in

the evaluation of cassava varieties by the scientists with other user groups.

Stage III. Laying out, management and evaluation of OFT

In consultation between the farmers and scientists, and on the basis of character

preference of cassava varieties, as indicated in the varieties' ranking (Table 3), it was

decided to include 1 1 cassava varieties, comprising three released varieties, one improved

variety, four pre-released varieties and three popular land races. The varieties selected

for the trial were:

Released varieties:

1. Sree Vishakom (H-1687)

2. Sree Sahya (H-2304)

3. Sree Prakash (S-856)

446

SOCIO-ECONOMIC BIO-PHYSICAL

SMALL LAND HOLDINGS

POOR KNOWLEDGE

ABOUT PRODUCTION

AND PROCESSING

MANAGEMENT

LACK OF CASSAVA

BASED COTTAGE

INDUSTRIES

NON AVAILABILITY

OF IMPROVED SHORT-

DURATION VARIETIES

LOW PRODUCTIVITY

OF CASSAVA

SEVERI

RODEN

DAMAC

HIGH INCIDENCE

OF MOSAIC

LODGING DUE T<

HEAVY WIND

Figure 3. Problem-cause relationshipfor low productivity of cassava under lowland

conditions in Anacode village, Trivandrum, Kerala, India.

447

SOCIO-ECONOMIC BIO-PHYSICAL

SMALL LAND HOLDINGS

POOR KNOWLEDGE

ABOUT PRODUCTION

AND PROCESSING

MANAGEMENT

NON AVAILABILITY

OF IMPROVED SHORT-

DURATION VARIETIES

LOW PRODUCTIVITY

OF CASSAVA

LOW YIELD

LACK OF CASSAVA

BASED COTTAGE

INDUSTRIES

CULTIVATION MOSTLY

AS INTERCROP

LODGING DUE TO

HEAVY WIND

Figure 4. Problem-cause relationshipfor low productivity of cassava under upland

conditions in Anacode village, Trivandrum, Kerala, India.

448

Table 2. Matrix ranking of crops by farmers in Anacode village, Trivandrum

district of Kerala, India.

Characters Paddy Cassava Rubber Banana Vegetables

Food security 1 2 5 3 4

Profitability 5 4 1 2 3

Low pest and

disease incidence

4 1 2 3 5

Drought tolerance 5 1 2 4 3

Low input

requirement

4 1 2 3 5

Marketability 4 5 1 3 2

Source: Anantharaman et ai, 1994.

Improved variety:

4. M-4 (popular among farmers in other areas)

Pre-released varieties:

5. CI-649

6. CI-664

7. CI-731 (a selection from the local variety Kariyilaporiyan)

8. CI-732

Local varieties:

9. Karukannan

10. Monkozhunthan

1 1 . Kariyilaporiyan

While implementing the OFT on cassava, the consultative participation of

farmers, which emphasizes researcher managed and farmer-implemented trials, as

outlined by Ashby (1986), was resorted to. However, researcher management was

restricted to guidance provided to farmers in the management of the OFT. Considering

the comprehending ability of the farmers and their unfamiliarity with experimental

designs, the laying out of the OFT using a typical experimental design was found difficult

under actual farm conditions. Hence, in discussion with the farmers and in consultation

with a statistician, a suitable design (modified CRD with two replications) was

formulated, which would facilitate the laying out of the trials and still be adequate for

appropriate statistical analysis. Accordingly, two trials, one each under upland and

lowland conditions, using the 1 1 selected cassava varieties in two replications under two

types of management, namely recommended package of practices and farmers'

management, were laid out. They were closely monitored through fortnightly visits to

the village and with active cooperation of the participating farmers. Group meetings

were also organized at the critical stages of the trials and the views and experiences of

449

Table 3. Matrix ranking of cassava varieties on the characters preferred by farmers

in Anacode village of Tri vandrum district in Kerala, India.

Character Sree M-4 Kariyila Mankoz Karu

Visakham poriyan hunthan kannan

Yield

Taste

Starch content

Root compactness 1

Season

2

4

5

3

3

2

4

4

5

1

3

2

4

3

2

I

Source: Anantharaman et al., 1994.

the individual farmers were recorded. Group consensus was arrived at in the conduct and

progress of the trials.

Cassava roots were harvested at the 7th month under the lowland condition and

at the 10th month under the upland condition. The harvested roots were exhibited in a

row, masking their identities, but with labels as VI, V2 etc. The selected groups of

scientists, farmers, farm women and traders were guided with an open-ended

questionnaire to register their opinion on positive and negative aspects of the roots. They

were also requested to rate the varieties on a five point continuum and to select the best

five varieties from among the 1 1 exhibited.

Results of FPR Cassava Varietal Selection

The most salient features of the preliminary stage of evaluation of cassava varieties are

as follows:

/. Performance of cassava varieties (Phase I)

The average root yields of the tested varieties are given in Table 4. The analysis

of the data indicate that the yield performance of the varieties under the recommended

as well as the farmers' management did not show any significant difference under both

production systems. However, significant differences existed amongst the varieties, with

CI-649 producing a significantly higher yield than the other varieties under the lowland

condition. The yields of CI-731, Mankozhunthan, H-1687 and H-2304 were not

450

statistically different, but were higher than those of the remaining varieties. The yield

performance of the cassava varieties, except H-1687 was found to be rather poor under

the upland condition (Anantharaman et al., 1995).

2. Evaluation of cassava varieties

Result of the evaluation by various groups on the basis of the ranks obtained by

each variety in terms of root characteristics, taste and suitability of the cassava varieties

for their end-use, are presented in Table 5. The Spearmen rank order correlation,

determined between the rank order of the varieties given by the various groups, indicate

that while the scientists' preferential order did not have agreement with that of other

groups, there existed agreement amongst those other groups. This shows that there were

differences in the preferential order of the varieties between scientists and end-users.

Analysis of the criteria used by the scientists and the other user groups for evaluating the

varieties, indicate that, while scientists gave importance to root weight, size, shape and

compactness, farmers considered number of roots (optimum being 5-7), uniformity in size

(optimum being 500-600 gm), skin and rind color, starch content, marketability,

attachment of the root to the base of the plant, root shape, general appearance, absence

of fibrous portion etc. as important criteria in selecting a variety. Farm women

considered taste, fast cooking, bitterness/sweetness of the cooked roots important in a

good cassava variety. The traders considered uniformity of roots (medium-sized), starch

content and skin color as important criteria. In addition, the farmers were of the opinion

that the cassava varieties suited to the lowland condition should be of medium stature and

should not grow too tall. Otherwise, it might lead to lodging. Moreover, the variety

should not have too much foliage, and at the same time, it should possess a higher starch

content and have less rat damage. As regard to stems, these should be flexible and

strong. Since there will be moisture at all times under lowland conditions, the roots

should resist rotting.

On the basis of the evaluation by various groups, five cassava varieties, i.e. CI-

649, CI-664, CI-731, CI-732 and H-1687 have been selected for further evaluation

during the subsequent phase.

Stage IV. Evaluation of selected clones (Phase II).

The five cassava varieties selected under Stage III were grown under both upland

and lowland conditions for validating the performance of these varieties for one more

season, and to select one or two most preferred varieties for popularization in the selected

village. The same process of evaluation of the varieties at time of harvest (excepting

scientists group) conducted during the earlier stage, was repeated. The analysis of the

performance under the lowland condition has been completed and the same under the

upland condition is in progress. The yield performance indicate that the cassava variety

CI-732 was the highest yielder (46.29 t/ha), followed by CI-649 (40.51 t/ha) and CI-731

451

Table 4. Yield performance of eleven cassava varieties in on-farm trials conducted

under lowland and upland conditions in Anacode village of Trivandrum

district in Kerala, India.

Average root yield (t/ha)

Variety Lowland Upland

29.25 30.15

26.15 12.83

19.81 12.83

26.72 14.40

32.13 19.50

55.00 14.18

22.13 6.66

21.81 12.15

30.91 8.78

19.69 17.55

28.50 16.65

H-1687

Karukannan

CI-664

S-856

CI-731

CI-649

CI-732

Mankozhunthan

Kariyilaporiyan

H-2304

Source: Anantharaman et al., 1995.

(39.72 t/ha). CI-732 also emerged as the most preferred variety by both the farmers and

the farm women. Matrix ranking of varieties based on yield and other characters by

farmers revealed that the preference for the varieties were in the order of CI-732, CI-

73 1 , CI-649 and CI-664. On the basis of overall performance and evaluation by various

user groups, the cassava varieties CI-732, CI-649 and CI-731 were the most preferred

ones, and these were taken to the next stage, popularization. Since CI-731 is a selection

from the popular local variety Kariyilaporiyan, it was decided to popularize only CI-732

and CI-649 in the selected village.

Stage V. Popularization of selected cassava varieties

Under the popularization scheme, the participating farmers acted as "seed

producers" for making available the disease-free planting materials of the preferred

varieties, as the non-availability of planting materials of high-yielding cassava varieties

was identified by Ramanathan et al (1987) as the most important constraint in the

adoption of these varieties by the farmers. Using the stems supplied by the seed

producing farmers, presently about ten farmers have grown the cassava varieties CI-732

and CI-649 in about one hectare of cassava area in the village. Efforts are underway to

formally release these varieties by the State Variety Release Committee, so that large-

scale TOT by the Kerala Department of Agriculture can be initiated.

The program of FPR in cassava is being continued in other villages of

452

Thiruvananthapuram district and is also programmed to extend to other regions of the

state.

Problems Encountered in the FPR on Cassava

1. Availability of planting material

Availability of disease-free high-quality planting material of new cassava varieties

at the right time and in the right quantity continues to be a serious constraint in

conducting these trials in large numbers and over various regions of the state. The

absence of any agency for large-scale multiplication and distribution of planting material

of improved varieties of cassava in India further aggravates this problem.

2. Laying out of OFT

In spite of adopting a simplified experimental design which was discussed with

the farmers, the actual conducting of the trial was found difficult, especially under

lowland conditions. An area of 0.8-1 .0 ha was needed for conducting the trial. Getting

such a big plot in the lowlands was difficult, since channels dug in between the plots for

drainage rendered them unsuitable for laying out a varietal trial with 10-12 varieties in

two replications. Moreover, as bunds have to be made around each subplot to demarcate

the replications, additional labor was required, which in turn increased the expenditure

in the cultivation. The undulating topography of the land also at times made the laying

out the trials difficult, particularly under the upland condition.

3. Organizing and conducting evaluation

Collection of various members of the evaluation groups, especially of the traders

and organizing the evaluation on a particular day was found to be difficult. Often the

traders go away for their business and the rest of the evaluators have to wait for hours.

There were occasions, in which the evaluation had to be postponed until the subsequent

day.

4. Harvesting and marketing of roots

During the initial phase of evaluation, about 50% of the plant population was

harvested to get accurate yield data of the varieties. This created problems in marketing

as these could only be sold a day after harvest due to the detailed evaluation on the day

of harvest. Resorting to a sample harvest also had its own problems. Since the majority

of the farmers preferred to market the roots on a contract basis, sample harvesting, which

created vacant spots here and there in the cassava plot, always resulted in a lower price

as compared to a full plot of cassava.

5. Labelling and storage of planting materials

Careful labelling of the varieties and the separate storing of the stems of each

453

variety is very important to avoid mixing up of varieties and for conducting subsequent

trials in the next season. With the stems of 1 1 varieties looking more or less similar, the

farmers expressed difficulty in careful identification, labelling and storage of stems of

each varieties at the time of harvest.

Table 5. Rank order of cassava varieties based on evaluation by user groups and scientists

in Anacode village of Trivandrum district in Kerala, India.

Ranking by user groups

Variety F(irmers Farmi women Traders Scientists

H-1687 2 6 6 3

Karukannan 3 5 3 11

CI-664 5 11 8 2

S-856 9 2 6 7

CI-731 4 3 3 4

CI-649 1 1 3 1

CI-732 8 7 9 8

M-4 6 4 1 9

Mankozhunthan 7 10 9 5

Kariyilaporiyan 3 3 4 6

H-2304 11 9 10 10

Degree of agreement between user groups:

Scientists vs Farmers0.39NS"

Scientists vs Traders0.1 3NS

Scientists vs Farm women 0.20'-s

Farmers vs Traders 0.65"

Farmers vs Farm women 0.49'«

Traders vs Farm women 0.80.

" NS = Not significant

Source: Anantharaman et al. , 1995.

** = Significant at \% level

REFERENCES

Anantharaman, M. and S. Ramanathan. 1986. Report of Lab-to-Land Programme Phase II,

1982-84. CTCRI, Trivandrum, Kerala, India. 27p.

Anantharaman, M., S. Ramanathan, S.G. Nair and T.V.R. Naryar. 1994. Farmers participation

in cassava varietal evaluation. RPF II (1994-95). CTCRI, Trivandrum, Kerala, India.

Anantharaman, M., S. Ramanathan, S.G. Nair and T.V.R. Nayar. 1995. Farmers participation

in cassava varietal evaluation. RPF II (1995-96). CTCRI, Trivandrum, Kerala, India.

Anantharaman, M. andS. Ramanathan. 1996. Socio-economic discriminants for successful cassava

technology transfer programme. In: G.T. Kurup, M.S. Palaniswami, V.P. Potty, G. Padmaja,

S. Kabeerathumma and Santha V. Pillai (Eds.) Tropical Tuber Crops. Problems, Prospects and

Future Strategies. Oxford & IBH Publishing Co. Pvt. Ltd., New Delhi, India. pp.537-543.

Ashby, A.J. 1986. Methodology for the participation of small farmers in the design of

on-farm trials. Agricultural Administration 22:1-9.

Ramanathan, S., M. Anantharaman and K.R. Lakshmi. 1987. Constraints in adoption of

high yielding cassava varieties. Indian. J. Extension Education 23(3&4):55-59.

454

FARMER PARTICIPATORY RESEARCH IN CASSAVA SOIL MANAGEMENT

AND VARIETAL DISSEMINATION IN VIETNAM

Nguyen The Dang\ Tran Ngoc Ngoan1, Le Sy Loi\

Dinh Ngoc Lan1 and Thai Phien2

ABSTRACT

Farmer Participatory Research (FPR) in Vietnam has been carried out since 1994 in

collaboration with CIAT, with the objective of improving the adoption of soil conservation

practices in cassava fields. Two villages in Pho Yen district, Bac Thai province; one in Thanh

Hoa district, Vinh Phu province; and one in Luong Son district of Hoa Binh province were

selected as pilot sites for implementing the FPR methodology.

In 1994: By using RRA and PRA methods in conducting diagnostic surveys, some main

limiting factors in cassava production were identified, such as lack of suitable planting methods

for soil erosion control and lack of knowledge about balanced fertilizer application and about high

yielding varieties. Therefore, demonstration plot with 17 treatments on different ways to improve

soil fertility and methods to control soil erosion, were established at the Agro-forestry College in

Thai Ngyen, Bac Thai.

Farmers' field days were held to show the demonstration plots to farmers and

extensionists from two of the selected districts in mid Nov, 1994. Based on the results and

discussion, seven treatments were identified by farmers as promising treatments for 1995.

Farmers also discussed how to arrange these in simple FPR trials in their own fields.

In 1995: Twenty five farmers of two villages in Pho Yen and ten farmers in Thanh Hoa

districts participated in the project by conducting research on their own fields. At time of harvest,

a farmers field day was held in both districts in mid Nov, 1995. Fanners and researchers joined

in the harvest and in the discussion of the results. Some best treatments were identified. The

treatments of cassava intercropped with peanut and contour hedgerows of vetiver grass, combined

with balanced NPK application, was considered as the most promising practice at both pilot sites,

as soil erosion losses were reduced by 20-40% compared to the check plot of cassava grown in

monoculture and without hedgerows. In Pho Yen district, cassava yields in this treatment were

about the same as the check plot, but net income increased 9-36%. In Thanh Hoa, cassava yields

increased about 9% compared to the check plot, while net income increased by 23%. In this

location cassava intercropped with peanut increased net income from 131 to 273% over cassava

monoculture. Farmers who tested new promising clones considered KM60 and CM4995-7 as the

most suitable for their conditions; these clones increased yields from 1 .7 to 4. 1 t/ha over the check

variety Vinh Phu.

These initial results are encouraging more and more farmers to participate in the FPR

trials. The number of farmers participating in 1996 increased and some of them can conduct the

trials now by themselves.

INTRODUCTION

In terms of area planted, cassava (Manihot esculenta Crantz) is the fifth most

important food crop in Vietnam, after rice, maize, sweet potato and vegetables. Cassava

fresh roots are used as human food and animal feed, but most cassava is processed into

dried chips or cassava starch, which are used to make monosodium glutamate, alcohol,

1 Agro-forestry College of Thai Nguyen University, Thai Nguyen city, Bac Thai, Vietnam.


455

candies, etc.

Cassava is grown mainly on hilly land in Vietnam. According to the literature

(Howeler, 1981), to produce a yield of 15-20 ton fresh roots per ha, cassava absorbs

about 75-100 kg N, 35-50 kg P205 and 105-140 kg K2O/ha. Therefore, the crop may

deplete the nutrients in the soil, especially if farmers remove from the field not only the

roots but also the stems and leaves. Farmers have long experience in growing cassava,

and have tried to improve their practices to maintain high cassava yields year after year,

such as the making of contour ridges when growing cassava on sloping land, or

intercropping cassava with peanut or black bean. But the yield of cassava was still low,

because of the lack of good planting methods to control soil erosion, as well as the use

of unbalanced fertilizer applications; they also lack good varieties and knowledge about

how to use peanut residues as green manure for cassava.

A lot of research has been done on various aspects of agriculture including

cassava, but few of these technologies have been put into practice, or they are not as

efficient as the farmers' practices. One of the most limiting factors in transferring new

technologies to farmers is that most research has been conducted at research stations

under very good management, very different from the real farm conditions. On the other

hand, for farmers to know how to apply the new technologies, they need to do them first

themselves and to evaluate them according to their own criteria; or they want to observe

how their neighbors apply the new technologies first. Given this fact, it is necessary to

change the methods used in research and the transfer of technologies, in order to adapt

to farmer's conditions.

Farmer Participatory Research (FPR) in Vietnam has been carried out since 1994

in collaboration with CIAT, with the objective of improving the adoption of soil

conservation practices in cassava fields.

FPR PROJECT IN VIETNAM

Two villages in Pho Yen district of Bac Thai province, and one village in Thanh

Hoa district of Vinh Phu province were pre-selected as the most suitable pilot sites for

implementing the FPR methodology.

To impliment the FPR methodology the following activities were carried out:

1 . Diagnostic surveys were conducted in the pilot sites using RRA and PRA methods in

order to better understand the existing farming practices and to hear the farmers' opinions

about how to solve their limiting factors.

2. Demonstration plots were established at the Agro-Forestry College of Thai Nguyen

University in Bac Thai, in order to show farmers a large number of management options

that can be used to reduce erosion.

3. Four types of FPR trials were conducted by farmers on their own fields:

- Soils erosion control by using different soil/crop management practices

- Cassava intercropping with peanuts, black beans etc.

456

- Variety testing

- Fertilization

4. Farmers field days were organized at harvesting time to discuss and evaluate the

results of the FPR trials, as well as to identify the most promising treatments for next

year.

Some Initial Results of the FPR Project

1. Diagnostic Surveys at Pilot Sites.

Using RRA and PRA methods, we surveyed two potential pilot sites in 1994,

i.e., Pho Yen district of Bac Thai province and Thanh Hoa district of Vinh Phu province;

these were selected as being most suitable for the FPR project. In 1995, another site in

Luong Son district of Hoa Binh province was selected.

Table 3 shows that the climate in all three sites is subtropical with an average

rainfall of 1500-2100 mm/year and considerable monthly fluctuations; the highest rainfall

occurs during the summer months of June to September and almost 80% of total annual

rainfall is concentrated in this period. This is one of the main causes for severe soil

erosion on steep lands.

Cassava is grown mainly on sloping land in the selected areas. In Pho Yen

district, cassava is grown on gentle slopes with a light textured sandy loam soil. This

soil is very susceptible to erosion by water. Thus, the soil has become depleted of

nutrients, especially potassium. Although cassava is grown on much steeper land in

Thanh Hoa and Luong Son districts, the soil texture is a heavy clay, which is more

resistent to erosion than the light soil in Pho Yen district. Another problem is that the

eroded soil is deposited in the rice fields at the bottom of the hill where it causes a

reduction in rice yields.

In both Thanh Hoa and Pho Yen districts, cassava occupies a rather important

position among field crops in terms of the income of farm households (Table 1). It is

usually ranked second, after rice, in terms of area and income.

The data of the RRA (Tables 1 to 4) have shown that cassava yields in the pilot

sites are rather low (8-15 t/ha) for the following reasons:

1 . Cassava is grown mainly on sloping land with such practices as contour ridging and

intercropping with peanut (or black bean). Cassava has a slow initial growth and the

plants do not cover the soil enough during the rainy months to prevent the direct impact

of rain drops on the soil surface. The run-off water carries away both nutrients and soil.

Therefore, cassava yields have decreased to only 3-4 t/ha in some plots after 10-15 years

of continuous cassava production.

2. On average, fertilizers applied to cassava (Table 3) consists of only about 5-10 t/ha

of organic (mainly pig) manure, together with 20-50 kg N, 10-50 P205 and 0-160

K2O/ha. Farmers also lack experience about how to use fertilizers and they lack credit

to purchase inputs for cassava. The number of households that use chemical fertilizers

457

for cassava was less than 50% of total households interviewed.

3. The local variety Vinh Phu green and a few other exotic varieties, such as Canh Ng

and Du varieties, have been grown for a long time without any regeneration practices.

4. Traditionally cassava roots are mainly used for food and animal feed, while some

small quantities are sold in the market when money is needed. Cassava is processed into

dry chips after manual cutting with a knife; this requires a lot of labor. In Dong Rang

village, however, more than 50% of cassava is sold as fresh roots.

5. The demand for cassava products, both for home consumption (mainly pig feeding)

and for marketing, seems to be increasing. The greatest difficulty farmers face is the loss

of productivity of the soil. This is thus a good opportunity to join with them in

conducting on-farm testing of more productive and more sustainable management

practices at these three pilot sites.

2. Demonstration Plots on Soil Erosion Control and Farmer's Field Days at the

Agro-forestry College.

Based on previous research on soil erosion control using various soil/crop

management practices, a demonstration plot with 17 treatments was established on about

20% slope in the Agro-forestry College in Thai Nguyen in 1994. These plots gave a

good picture of various alternatives for growing cassava on slopes, so farmers could

select the most promising treatments during the farmer's field days. The data in Table

5 show the effect of treatments on cassava yield and soil erosion, as well as the economic

returns and the farmers' preferences. Treatments with hedgerows of Tephrosia candida,

Flemingia congesta and vetiver grass, or the intercropping with black bean and with

Tephrosia hedgerows gave very good results with respect to soil eroison control; total soil

erosion decreased between 47.7 and 61.9% as compared to the check plot (treatment 1).

In treatment 10, with vetiver hedgerows, only 7.25 ton dry soil/ha was lossed, while

cassava fresh root yield was maintained at 20.5 t/ha. In treatment 4, with balanced NPK

and organic manure application, the cassava yield reached 26.6 ton fresh roots/ha, but

dry soil loss was still high at 14.4 t/ha. After the results were discussed with farmers

during the field day at the end of Nov, 1994, some treatments were selected for on-farm

testing in 1995.

In 1995, the same demonstration plots were continued with 16 treatments:

treatment 6 was replaced by NPK and intercropping with peanuts, while treatment 15 was

replaced by NPK and no tillage. The results of soil loss measurements and cassava yields

are given in Table 6. They show the same trend as in 1994. Soil losses in treatments

6. 8, 9, 10, 11 and 13 decreased between 59.8% and 81.3% as compared to the check

plot. Highest cassava yields were achieved in treatments 12, 4, 5, 16, 10 and 7. Gross

and net income were the highest in treatments 12, followed by treatments 4, 5, 6, 10 and

16.

458

Table 1. Secondary data of Luong Son district of Hoa Binh, Thanh Hoa district of

Phu Tho, and Pho Yen district of Thai Nguyen provinces in north Vietnam.

Province Hoa Binh Phu Tho Thai Nguyen

District Luong Son Thanh Hoa Pho Yen

Latitude (°N) 20° 50'21o30.

21° 20'

Altitude (masl) 30-40 80 40

Soils dark red clay

typic Paleustult

red clay loam while sandy loam

Rain fall (mm) 1600-1800 1700-2000

Temperature (°C) 23-25 22-24

Landscape hilly hilly rolling

-rice in lowlands in lowlands in lowlands

-cassava on <25% slope on <40% slope on <20% slope

Main crops (ha)

-rice (crop land) 4,690 3,580 7,200

-cassava 838 1,500 650

-sweet potato1' 402 670 1,400

-peanut 798 345 1,212

-maize 680 732 700

-mungbean 370 385 500

-tea 917 1,075 1,181

-forest 13,036 14,250 14,886

Yield (t/ha)

-cassava 6.5-7.0 4 6 9.7

-rice 2.3-2.5 2 3 3.2

-sweet potato 5.5-6.0 4.5-5.0 5.5

-peanut 0.8-0.9 0.9-1.0 0.9

-maize 1.5-2.0 1.8-2.2 5.0

-soybean 0.5-0.7 0.6-0.8 0.7

Farm size (m2/fam.)

-total 9,500-10,500 2,000-15,000 7,000-11,000

-cassava 1 ,000-2,200 1 ,500-2,000 720-1,080

-rice 600-800 500-5,000 360-6,400

-garden 0-5,000 0-5,000 1,800-5,000

-tea 0-3,200 0-2,500

-sweet potato 200-400 350-400 360-1,080

-trees 300-500 500-600 500-720

"mainly as winter crop on rice land.

459

Table 2. Population, land classification and land use, as determined from Rapid Rural Appraisals

(RRAs) conducted in four FPR pilot sites in Vietnam in 1996/97.


District Luong Son Thanh Hoa Pho Yen

Village Dong Rang Phuong Linh

Population

Tien Phong Dae Son

-no. of households (hh) 81 275

-no. of hh. interviewed 40 158 6 35

-ethnic group Muong (90%)/Kinh" Kinh Kinh Kinh

-no. of people/hh 6-7 5.2 5.3 6.1

-length of time settled >20 >25 >20 >20

(year)

Land characterization

-lowlands (ha) 27 86

-upland (ha) 95 (36 ha planted/yr) 29

-cassava (ha) 30 15 50 40

-slopes (%) <25 <40 <20 <10

-soil type, fertility clay, medium fertile clay, low fertility sandy loam

low fertility

sandy loam

low fertility

-erosion medium high medium low

Land use

-uplands cassava, taro, peanut, cassava, peanut, cassava cassava

sugarcane, fruits sweet potato peanut sweet potato

forestry tea, palm, bamboo sweet potato peanut

soybean

-lowlands rice (2 crops) rice (1 crop) rice (2 crops) rice (2 crops)

peanut, sweet potato, fish in paddy sweet potato sweet potato

maize, soybean, fish ponds fish ponds

sugarcane (chewing)

Area main crops (m2/hh)

fish ponds

-summer rice 2,500 3,700 4,500 3,100

-spring rice 3,100 2,160 2,460 2,063

-cassava 4,000 720 4,320 977

-sweet potato 300 500 1,080 954

-peanut 350 420 2,040 634

-soybean, mungbean etc 390 385 - 526

-tea 360 400 - -

-garden 1,000

9,500

1,800

7,925

.

Total farm size 11,940 6,191

Land ownership(%) 100 100

no. of parcels/hh 8 7

Animals buffalo buffalo buffalo buffalo

cattle for meat cattle for plowing fish fish

(± 100 head)

fish fish

"Kinh = lowland Vietnamese

460

Table 3. Cropping systems, varieties and agronomic practices, as determined from RRAs conducted

in four FPR pilot sites in Vietnam in 1996/97.


District Luong Son Thanh Hoa Pho Yen Village

Dong Rang Phuong Linh

Tien Phong Dae Son

Cropping system"

-upland tea C monocult. C + P or C + B C monocult. or

C+T C + P or 2 yr C rot. C-P rotation

C monocult. tea, peanut with 2 yr fallow or C-B, C-SP

Varieties

peanut, maize maize sweet potato sweet potato

-rice CR 203, hybrids DT 10, DT 13, DT 10, DT 13 CR203

from China CR203 CR203 DT 10, DT 13

-cassava Vinh Phu, local Vinh Phu, local Vinh Phu

Du, Canh Ng

Vinh Phu

Cassava practices

-planting time early March early March Feb/March Feb/March

-harvest time Nov/Dec Nov/Dec Nov/Dec Nov/Dec

-plant spacing (cm) 100x80 80x80; 80x60 100x50 100x50

-planting method horiz. /inclined horizontal horiz. /inclined horizontal

-land preparation buffalo/cattle by hand/cattle buffalo buffalo

-weeding 2 times 2 times 2 times 2 times

-fertilization basalbasal + sidea

basal + side" basal + side4)

-ridging mounding flat flat flat

-mulching rice straw peanut residues peanut residues peanut residues

-root chipping hand chipper knife small grater small grater

-drying 3-5 days 3-5 days 2-4 days 2-4 days

Fertilization

-cassava

-pig manure (t/ha) 5 5 3-5 8-11

-urea (kg/ha) 0 50-135 83 83-110

-SSP (18% P2Os) (kg/ha) 50-100 0 140 0-280

-KC1 (kg/ha) 0 0 55 0-280

-rice

-pig/buffalo manure (t/ha) 5 0 - -

-urea (kg/ha) 120-150 80 - -

Yield (t/ha)

-cassava 10-12 8-15 8.5 8.7

-rice (per crop) 3.3-4.2 4.2 3.0-3.1 2.7-3.0

-taro 1.9-2.2 - - -

-sweet potato - - 8.0 3.3

-peanut 0.8-1.2 0.5-1.1 1.4 1.3

pigs (kg live weight/year) 100-120 - - -

C=cassava, P= peanut, B=black bean, T=taro, M=maize

C + P=cassava and peanut intercropped; C-P=cassava and peanut in rotation

urea at 2 MAP

urea when 5-10 cm tall; NPK +FYM when 20 cm tall

NPK when 30 cm tall; hill up

461

Table 4. Labor use, crop utilization and farm income, as determined from RRAs conducted in four

FPR pilot sites in Vietnam in 1996/97.


District Luong Son Thanh Hoa Pho Yen Village

Village Dong Rang Phuong Linh

Tien Phong Dae Son

Labor (mandavs/ha) cassava rice cassava rice cassava rice cassava rice

-land prepartion 30 30 44 35 28 30 27 29

-planting 20 30 45 25 20 25 20 25

-weeding 45 40 35 35 30 40 30 40

-irrigation - 10 35 - 10 - 10

-fertilization 10 20 20 10 17 12 16 12

-harvest 30 35 50 35 36 32 34 32

-chipping/drying 45 - 45

-thrashing 20 28 50 28 48 27

Total 180 185 239 203 181 177 175 175

Prices (done/ke)

-fresh cassava 300-400 500 400

-rice 1,500 1,500 1,500

-peanut 3,500 3,300 3,500

-urea 3,000 3,100 2,700

-SSP 850 780 700

-KC1 2,500 2,700 2,500

Utilization (%)

-rice 100% hh . use 100% hh. use 100% hh. use 100% hh . use

-cassava -fresh roots 60% (60% to market) 15% (5% market) 20% (all home) 17% (all home)

-dry chips 40% (pig feeding) 85% (5% market) 80 (10% market) 83 (5% market)

-stems firewood firewood firewood

-leaves fish or pigs fish or pigs

Market use of cassava

-fresh starch, maltose, alcohol alcohol - ■

-dry chips

human food, pig feed

pig feed alcohol pig feed pig feed

Income (mil, dong/hh./year)

-crops 3.5-4.5 5.4

-pigs, chickens, ducks 1.5-2.0

-others 1.0-1.5 1.5-2.5

6.1 3.1

0.13

08

7.4

3.4 3.2

2.3 3.0

1.1 0.2

3.5

Total 6.0-8.0 7-8

Costs and income (mil, dong/ha/yr)

Gross income crops 3.7

Production costs crops 2.5

Net income crops 1 .2 0.134

Note: 1US$ is about 11.000 dong in 1996/97

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During the farmers' field day, farmers from the pilot sites had the opportunity to see,

discuss and select the most appropriate treatments. Most of the farmers based their

choice on two main criteria: the quantity of soil lossed by erosion and cassava yield. The

largest number of farmers selected treatments 9, 6 and 10. Although treatment 12

produced the highest net income, only 32.4% of farmers considered this treatment very

good.

3. Farmer Participatory Research (FPR) Trials in 1995.

Four different components of technologies were tested on farmers' fields:

- erosion control

- intercropping systems

- fertilization

- varieties

As a result of the farmers' field day held at the Agro-forestry College in 1994, farmers

selected the treatments that they wanted to test on their own fields.

A total of 35 farmers volunteered to conduct FPR trials: 18 in Tien Phong and seven

in Dacson villages of Pho Yen district, and ten in Phuong Linh village of Thanh Hoa

district.

3.1. Results ofsoil erosion control trials

On sandy loam soils of two villages in Pho Yen district, having slopes ranging from

10 to 25%, the results of six FPR trials show the same trends. Treatments 4 and 5

reduced soil losses between 51.1 and 59.9% as compared to the farmers' practices of

growing cassava in monoculture. The reduced erosion is due to the hedgerows and the

intercrops. However, the cassava yield was only 10.5 t/ha in treatment 4 and 12.1 t/ha

in treatment 5, which are lower than that of the farmers' practice. But these treatments

also produced between 0.15 to 0.3 t/ha of peanuts (in dry pods), so the net income of

treatment 5 was among the highest while the cost was not as high as that of the farmers

practice (Table 7).

In Phuong Linh village of Thanh Hoa district in Vinh Phu province, ten farmers

participated in the project to conduct trials on their own fields with slopes ranging from

32 to 45%. The results, shown in Table 8, indicate that all treatments with hedgerows

reduced soil erosion between 17 and 21% as compared to the check plot, while the

cassava yields were between 3 and 29% higher than in the check plot (treatment 2). A

simple economic analysis of the trial indicate that treatment 6 produced the highest net

income of 23.57 mil. dong/ha, while the farmers practice in treatment 2 produced only

11.13 mil. dong/ha, which is less than half of that of treatment 6. After discussing the

results of the FPR trials, nearly all farmers in Thanh Hoa and in Pho Yen selected the

treatment of cassava intercropped with peanut, with NPK application and with vetiver

grass hedgerows as the best management practice.

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3.2. Results of intercropping trials

The survey conducted in 1994 identified some commonly used systems of cassava

intercropping with peanut or black bean. Cassava was usually planted with 1.4 m

between rows and 0.6 between plants. The intercrops were planted along two sides of

the cassava rows. So, it was decided to compare these two systems with the traditional

system of growing cassava in monoculture. In 1995, seven farmers in Tien Phong

village conducted these intercropping trials, each with three treatments. Cassava and

intercropped plants were distributed as follows: cassava was planted at 0.9x0.7 m with

two rows of intercrops between cassava rows. Results of these trials (Table 9) show that

net incomes from intercropping were higher than from cassava monoculture. Cassava

intercropped with peanut increased net income by 45% over cassava monoculture,

because this treatment produced 12.3% higher cassava fresh root yields than the check,

as well as 0.71 1 ton dry pods of peanut/ha. Since, all stems and leaves of intercropped

peanuts were incorporated as green manure after the peanut harvest this may have

increased cassava yields. Cassava intercropping with black bean seems less promising

as the black bean variety used is a climbing bean, which climbs around cassava plants.

Cassava yields were affected by competition from these beans.

Cassava intercropping with peanut seems a very promising system, both for

increasing farmers' income and for soil conservation. Most farmers want to apply this

method as 100% of farmers selected this treatment as the best practice.

3.3. Results offertilizer trials

Some FPR fertilizer trials, each with various combinations of N, P and K,

together with pig manure, were conducted in the two villages of Pho Yen district in

1995. The results of these trials, shown in Table 10, gave farmers some idea about the

economic effects of fertilizer application. The farmers' own practice produced an

average cassava yield of only 10.9 t/ha, while the application of 10 t/ha of pig or buffalo

manure produced a yield of only 7.13 t/ha. The results indicate that potassium plays a

very important role for cassava (comparing cassava yields in treatments 5 and 6) in sandy

loam soils like those in Pho Yen district. It is very important to apply K to cassava if

farmers want to get higher cassava yields. On the other hand, when we compare cassava

yields in treatments 4 and 6, it is clear that cassava did not respond to phosphorus

application. So, farmers should apply P probably only once every three years.

Treatment 4 also produced the highest net income among these six treatments. It is very

important to know that cassava yields in this area can be maintained with the application

of organic manure combined with some chemical fertilizers, as shown in these trials.

468

Table 9. Average results of seven FPR intercropping trials with cassava conducted

in Tien Phong village of Pho Yen district in Bac Thai province of Vietnam

in 1995.

Treatments

Yield (t/ha)

(million dong/ha)

Gross Costs

cassava intercrop income

Net Farmer

income preference2'

Cassava monoculture 17.07 - 13.66 2.01 11.65 14

Cassava + black bean 16.62 0.263 14.87 2.25 12.62 57

Cassava + peanut 19.17 0.711 19.60 2.71 16.89 100

"Cost of fertilizers, manure and intercrop seeds:

80 kg N + 40 P2O5 + 80 K2O/ha = 1.01

10 t pig manure/ha = 1.00

40 kg black bean seeds/ha = 0.24

100 kg peanut seeds/ha = 0.70

2,Percentage of farmers choosing treatment.

million dong/ha

million dong/ha

million dong/ha

million dong/ha

Table 10 Average results of two FPR fertilizer trials with cassava conducted in Dae Son and

Tien Phong villages of Pho Yen district, Bac Thai province of Vietnam in 1995.

Cassava

yield

(million dong/ha)

Treatments Gross" Costs' Net Farmer

(t/ha) income income preference2'

Farmer's practice3' 10.92 8.74 2.87 5.87 -

NoPoKo+ 10 t FYM 7.13 5.70 1.00 4.70 -

NoP«K8o+ 10 t FYM 14.15 11.32 1.57 9.75 -

N8oPoK8o+10 t FYM 15.65 12.52 1.78 10.74 100

N«>P4oKo+10 t FYM 13.87 11.10 1.68 9.42 -

N8oP4oK8o+ 10 t FYM 15.65 12.52 2.01 10.51 81

"Prices : fresh cassava roots

urea (45% N)

SSP (17% P2O5)

KC1 (60% K2O)

pig manure

800d/kg

2,500 d/kg

1,000 d/kg

2,500 d/kg

100,000 d/t

2,Percentage of farmers choosing treatment.

3)On average applied 20.8 t pig manure, 37.1 kg P2Os and 137.5 K2O/ha

469

3.4. Results of variety trials

In 1995, two promising clones, i.e. KM60 and CM4955-7, were evaluated on

farmers' fields. Table 11 shows that these clones had fresh root yields between 1 1.6 and

28.5% higher than the local check variety, Vinh Phu. Among 18 farmers who evaluated

these trials, 61.1% selected KM60 and 77.8% selected CM4955-7 for planting next year.

Table 11. Average results of three FPR cassava variety trials conducted in Tien

Phong village of Pho Yen district, Bac Thai province of Vietnam in 1995.

(million dong/ha)

Cassava

Variety yield Gross Net Farmer

(t/ha) income income" preference2'

Vinh Phu 14.30 11.44 9A3 Vl

CM4995-7 18.37 14.70 12.69 78

KM-60 15.96 12.77 10.76 61

"Cost of fertilizers + manure = 2.01 million dong/ha.

2)Percentage of farmers preferring the variety.

4. Farmers' Field Days

The first farmers' field day was held for farmers from both pilot sites at the

Agro-forestry College in Thai Nguyen, to evaluate the demonstration plots and to discuss

the technology components to be tested on their own fields in 1995.

The second farmers' field days were held both at the pilot sites and at the Agro-

forestry College, one day in each location. A very important aspect of FPR is that

farmers, researchers and extensionists work together in conducting the trials. Thus, all

of us joined and worked together during harvest, evaluation and the discussion to select

the best options and to decide on the most appropriate technologies to be included in the

design of the work plan for the next season.

Farmers' preferences are presented in the last column of Tables 7, 8, 9, 10 and

11. Based on this, the following technologies were considered as best adapted to the

farmers' conditions (Tran Ngoc Ngoan et al., 1995):

1. Cassava intercropped with peanut, with application of 60 kg N + 40 P205 + 120 K20

+ 10 ton pig manure/ha, and with vetiver grass hedgerows to reduce soil erosion and

increase net income.

2. Cassava intercropped with peanut with a basic fertilization of 10 ton pig manure, 80

kg N + 40 P205 + 80 K20/ha for soil conservation and increasing net income.

3. Both KM60 and CM4955-7 were selected for the next evaluation.

470

5. On-going Work in 1996.

These initial results are encouraging more and more farmers to participate in the

FPR trials. The number of farmers participating in 1996 increased to 57 households, of

which 37 in Pho Yen district, 13 in Thanh Hoa district and 7 in Luong Son district.

Also, some treatments have been adjusted in accordance with the farmers' own

ideas, such as the use of the new variety KM60 in combination with treatments on soil

erosion control. In 1996, the variety trials increased both in number of farmers

participating (20 farmers) and in the number of promising clones tested (5 promising

clones/trial).

CONCLUSIONS

After two years of work and some initial results, we have learned a lot about the

use of the FPR approach, and farmers also know why we need to work more closely

together with them; they are encouraged to contribute their local experiences while

working together as a group. FPR is very useful for us, because by conducting this type

of research together with farmers on their own fields, other problems can be identified.

We can get feedback information about what farmers want to do and what they don't

want to do. A strong linkage between researchers, farmers and extentionists in the

technology development process was established. The learning from each other, while

working closely with farmers, will increase the adoption of new technologies by farmers

and will also improve the relevance of the research conducted by us. It is also

encouraging the process of farmers learning from farmers. However, while working with

farmers we need to learn more about the FPR methodology and improve our skill in

working with different groups of farmers.

REFERENCES

Howeler, R.H. 1981. Mineral Nutrition and Fertilization of cassava (Manihot esculenta Crantz).

CIAT Series No. 09 EC-4 Centro International de Agricultural Tropical (CIAT), Cali,

Colombia. 52 p.

Tran Ngoc Ngoan, Nguyen The Dang, Le Sy Loi and Dinh Ngoc Lan. 1995. Variety selection

and technological management of cassava to maintain soil fertility and high income in

the mountainous area. Final Report 1991-1995. (in Vietnamese)

471

FARMER PARTICIPATORY RESEARCH IN SOIL MANAGEMENT IN

INDONESIA

W.H. Utomo1, Suyamto2, H. Santoso1 and A. Sinaga1

ABSTRACT

Soil degradation, both due to soil erosion and nutrient removal, is a major problem in

cassava fields. Most of the existing management technologies that have been developed have had

little success in adoption. Some of the reasons are that the technology developed is technically

oriented, based on experiment station research with very little farmer involvement.

Research on "Farmer's participation in developing management technologies for cassava-

based cropping systems" was carried out in farmers' fields in Wates and Dampit subdistricts of

Blitar and Malang districts of East Java, respectively. The research is planned for five years, with

the first year activities of : (a) Rapid Rural Appraisal (RRA) and diagnostic surveys for

identification of the problems encountered by cassava farmers, and (b) establishment of

demonstration plots to test and to show to farmers the management technologies that have been

identified and selected by the collaborating farmers. Activities planned for the second and

following years include the testing of the most attractive technology options on farmers' fields by

farmers themselves.

In general, most farmers had already been aware of the problem of soil degradation in

their fields, and had tried some management technologies for overcoming this problem. However,

since the technology is too complicated, laborious and costly, they were unwilling to adopt. In

fact, most farmers were very keen to adopt any attractive new technology, if the technology is

simple, does not imply a lot of extra costs, and is easy to be adopted. This was indicated by the

number of farmers willing to participate in the second year to test some technologies in their own

fields.

INTRODUCTION

Soil deteriotation and land degradation are common and serious problems in

Indonesian cassava fields. Therefore, a lot of people believe that these problems arose

from cassava cropping. With its high dry matter yield, cassava removes a lot of plant

nutrients from the soil. In addition, a high erosion rate, especially during the early

growth phase, is often observed from cassava fields.

It is true that the soil in most cassava fields is in very poor condition. However,

the soil deterioration is not only due to cassava. In fact, the soil has become in such a

critical condition, that cassava is the only crop that can grow and produce a reasonable

yield. For example, of the 300,000 ha planted to cassava in East Java more than 80%

is in critical condition.

Realizing the problem, many soil management technologies have been developed,

both to control soil degradation and to improve soil productivity. However, cassava

1 Brawijaya University, Malang, E-Java, Indonesia.

2 Research Institute for Grain Legumes and Tuber Crops (RILET), Malang, E-Java,

Indonesia.

472

farmers have hardly adopted these technologies. If they apply the technology, the

adoption process takes a very long time, and the application of the technology is only

temporary. This is not due to the lack of understanding of soil erosion and soil

management. A lot of studies have indicated that in most areas of marginal land, farmers

are already well aware of the problems of soil erosion, soil degradation and of ways to

overcome these problems (Utomo et al, 1994). However, technology adoption is another

matter. In most cases, farmers are reluctant to adopt the technology developed by

researchers, because the technology is too costly, too complicated or does not give direct

benefits. It seems that most researchers developed the technologies based on their own

ideas, without considering the farmers conditions and requirements. In addition, most

of the technologies are technically oriented and developed under experimental station

conditions. Thus, as stated by Henry (1994), researchers used a top-down approach.

Some sociologists and anthropologists (Fujisaka, 1989; Saragih and Tampubolon,

1991) have suggested that to develop a more adoptable technology, we should take into

account the farmers' conditions and farmers' requirements. Thus, the technology should

be more farmer-oriented. The methodologies used include what are called "On Farm

Research" and "Farmer Participatory Research" (FPR). Henry and Hernandez (1994)

have shown that FPR is very effective for the dissemination of new cassava varieties in

Colombia. The potential of FPR in soil management technology transfer has been

discussed extensively by Fujisaka (1991).

The work reported here aims to study the effectiveness of FPR for soil

management and varietal dissemination to cassava farmers in East Java, Indonesia. The

research was carried out at Ringinrejo village, Wates subdistrict of Blitar district, and in

Sumbersuko village, Dampit subdistrict of Malang district, and was planned for five

years. The report describes the first and second year's results.

FARMER PARTICIPATORY RESEARCH

The research started with a Rapid Rural Appraisal (RRA) to identify the problems

of cassava farmers, and to learn about the farmers' ideas on soil management. Based on

this discussion, demonstration plots were established to show a wide range of prospective

soil management technologies, after which farmers selected and tried some soil

management technologies in their own fields. The project staff helped farmers to conduct

this research.

Rapid Rural Appraisal (RRA)

A Rapid Rural Appraisal was carried out in August 1994 in Blitar and in Sept

1994 in Malang district. A team consisting of two soil scientists, one agronomist, one

agricultural socio-economist and one soil conservation extensionist (from Brawijaya

University, RILET and the Institute for Soil Conservation and Land Rehabilitation,

473

respectively), interviewed key farmers in the two villages covering the following topics:

a. Soil and land conditions

b. Agricultural practices (crops and varieties used, spacing, cropping systems,

fertilization, etc.)

c. Soil conservation and management practices

d. Socio-economic conditions

The main purpose of the RRA is to learn about the awareness and the perception

of the target farmers concerning soil degradation problems, and their understanding and

ideas about soil conservation and management practices.

To obtain more detailed baseline data, a diagnostic survey was conducted in Sept

1995 in Blitar and in Nov 1995 in Malang.

The results of the Rapid Rural Appraisal (Table 1) indicate that most farmers in

the study area are aware of the problems they encounter. The farmers know well that

their soil is in a very poor condition and a lot of work needs to be done to get a

reasonable yield. They are also well aware that soil degradation due to soil erosion is

occuring very rapidly. Hence, soil conservation, both the preventing of soil erosion and

the improving of soil fertility is essential.

The problems are that the land area owned by individual farmers is very small,

about 0.40- 1 .0 ha/household (also notice the results of the detailed survey given in Table

2). Hence, the income from farming activities is very low (around Rp

600,000/year/household). With this low income it is imposible for farmers to worry

about erosion and to manage the soil more effectively. Actually, the farmers are very

eager to practice better soil management in their fields. However, most of the

recommended soil management technologies are very expensive and require constant

maintenance. In addition, some soil management techniques (such as alley cropping) are

complicated and require a lot of time and labor for the technology to work well. At

certain times during the year, especially during the dry season and after planting, many

people go to the city to earn additional income. Therefore, there is often not enough

labor available to look after the soil management technology they want to practice.

Although a lot of farmers raise livestock (Table 2), they do not like to include

elephant grass barriers in their crop area. It seems this is due to strong competition

between the main crop and the elephant grass. Some farmers use leaves of Gliricidia

sepiwn which is planted as a fence, for livestock feeding, especially during the dry

season.

Demonstration Plots

Based on the information obtained through the RRA, a set of soil management

technologies was tested in the demonstration plots established both in Ringinrejo village,

Wates subdistrict of Blitar district, and in Sumbersuko village, Dampit subdistrict of

Malang district, both in East Java.

474

The soil management technologies tested in Blitar and Malang are given in

Tables 3 and 4, respectively.

All experimental activities, including land preparation, planting and the taking

of measurements, were done by the farmers, which were coordinated in a farmers' group

in each site. These farmers' groups consisted of 33 farmers in Ringinrejo and 23 farmers

in Sumbersuko.

The data given in Tables 3 and 4 show that some introduced soil management

technologies produced better results, both in terms of increasing farmer's income and

decreasing soil loss, than the traditional farmer's practice. Even though the alley trees

were still small in both sites, the practice of alley cropping was already able to decrease

soil losses due to erosion.

To obtain the perception of the farmers' group and of their neighbors to the soil

management technologies tested, field days were organized on April 28 and Sept 3, 1995,

for the Ringinrejo site, and on Oct 24, 1995 for the Sumbersuko site. In addition, to

broaden the view of the participating farmers, another field day was held at Jatikerto

Experimental Station of Brawijaya University in Jatikerto, Malang. Farmers evaluated

and discussed the soil management technologies that have been tested for many years at

this experimental station.

The opinion and selection priorities of farmers to the soil management

technologies are given in Table 5. It seems that the opinion and preference of farmers

to any technology is based mainly on what they see. They did not yet know the cassava

yield at Jatikerto, but the field showed that cassava planted with Gliricidia contour strips

grew very well. Hence, they choose this technology.

Although there was clear competition between the elephant grass and cassava, as

indicated by poor cassava growth close to the elephant grass strips, this technology is still

preferred by some farmers. These farmers argued that they need elephant grass to feed

their livestock. Crop competition could be decreased by the application of manure.

They also saw that the soil loss in the treatment with elephant grass strips at Jatikerto was

very low.

Some farmers in Ringinrejo still preferred planting cassava intercropped with

maize using the farmer's traditional wide spacing of cassava rows because they can use

more space to plant maize and other crops after maize. These farmers use maize as the

main family food.

475

Table 1. Results the of Rapid Rural Appraisal (RRA) conducted at Ringinrejo village, Wates

subdistrict of Blitar district in East Java, Indonesia, in Aug 1994.

Key issues Conditions Farmer perception Limiting factors

Soil - Thin top soil with - They understand that soil - Lack of capital

underlying limestone should be improved - Difficult to obtain

- Low nutrient content (esp. N, manure

P, K and some micronutrients)

Cropping

a.Species

b. Variety

c. Spacing

d. Planting date

e. Fertilizer

f. Yield

Maize as the main crop,

cassava as intercrop

Maize: local, Arjuno or

Hybrids

Cassava : local or Faroka

Maize: 100x20 cm

Cassava: 100x200 cm

Start of rainy season

Urea

Maize: 2-3 t/ha

Cassava: 5-8 t/ha

- Maize is the main

food, cassava is only a

security food or for cash

- Farmers plant the

variety available

- Farmers are able to

grow a second intercrop

after maize

Do not apply enough

Yields are

extremely low

High fluctuation of

cassava prices

Lack of information

about new varieties

Beginning of rainy

season is

unpredictable

Lack of capital

Soil and Land Conservation

a. Tree crops - Very few tree crops

b. Terracing

c. Contouring

d. Strip cropping

/alley cropping

- Improper terracing

- Some farmers practice

contour ridging

- Gliricidea is used as a fence

Farmers understood

well the importance of

soil conservation

Technology for soil

conservation is too costly

and too complicated

Gliricidea and

elephant grass used as

animal feed

Lack of capital

Lack of labor for

maintenance of

terraces

Farm size - 0.60 ha/household - Too small to obtain

enough income

Land distribution - Unequal land area - Need a lot of time and

labor- Fragmented land holdings

Farmers income - Rp 600.000/household/year"

Mobility - Many people move to the

nearest city temporarily to

earn additional income

- Limited work

opportunity at

at the village

"1USS = Rp 2100,

476

Table 2. Characteristics of the two project sites.

Characteristic Ringinrejo(Blitar) Sumbersuko(Malang)

1. Altitude (m above the sea) 420 500

2. Rainfall (mm/year) -1500 >2000

3. Soil Lithosol (Entisol) Latosol (Oxisol)

4. Topography undulating to hilly undulating to hilly

5. Total area (ha) 2,232 1,057

a. Upland (legal) 552 835

b. Plantation crops 857 -

c. Forest 159 -

d. Others 664 222

6. Crops (ha)

a. Upland rice 115 36

b. Maize 292 425.

c. Cassava 145 725.

d. Soybean 60 -

e. Peanut 30 -

7. Total Population 3,420 1,191

a. Farmers 3,283 641

b. Others 137 550

8. Livestock ownership

a. Cow/household

9. Income (US $/h.h./year)

a. Farming

b. Others

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479

Table 5. Farmer preference and opinion on soil management technologies

demonstrated in Ringinrejo (Blitar) and Sumbersuko (Malang) as well as

at Jatikerto Experimen Station in Malang, E. Java, Indonesia.

Farmei Soil management Net income Soil loss Farmers. opinions

preference treatment C000 Rp/ha) (t/ha/year)

1. Gliricidia contour strip 1,509" 39.6"

a little"'

- Cassava grows very well5'

- Soil loss is low

- Gliricidia leaves can be

used for livestock feed

2. Flemingia contour strip 1,451" 40.3"

a little41

- Cassava grows very well"

- No competition

- Flemingia leaves are good

for feeding goats

3. Elephant grass contour 1,737" 42.9" - Altough there was strong

strip none"' crop competition, the

soil loss is rather low

- Elephant grass used as

livestock feed

4. Calliandra contour strip 1,574" 38.6" - Calliandra leaves are good

for livestock feed

- Soil loss is low

5. Cassava + Maize

(farmers. practice)

7242) 41.12)- Need a wide cassava

spacing to plant

more maize

6. Farmers. practice4722' 47.42> -

7. Farmers' practice1,219s'

72.3" -

"Date are average values of Ringinrejo and Sumbersuko demonstration plots

2>Ringinrejo demonstration plots

"Sumbersuko demonstration plots

"'Soil loss observed at Jatikerto Experiment Station

"The opinions on cassava growth were based on observations made in Jatikerto Experiment Station

Participating Farmers' Experiments

After evaluating the soil management technologies tested at Ringinrejo and at the

Jatikerto Experiment Station, 15 farmers in Ringinrejo participated in the FPR project by

testing some selected technologies in their own fields. The technologies tested in the

farmers' fields are given in Table 6. Nine farmers conducted erosion control trials and

six farmers participated in variety trials. In Sumbersuko, experimental activities in the

second year still focussed mainly on the improvement of the demonstration plots.

480

Table 6. Soil management technologies tested by farmers in Ringinrejo in nine

erosion control and six variety trials in 1995/96.

Soil management Number of

technologies farmers"

1. Erosion control trials:

- Gliricidia contour strips 7

- Calliandra contour strips 3

- Flemingia contour strips 2

- Leucaena contour strips 1

- Elephant grass contour strips 2

- Intercropped with cowpea 2

- Control without strips 7

2. Variety trials:

- Faroka 6( + 6):>

- 15/10 5(+D

- SM-4772 6(+D

- Local(Ketela ijo) l(+4)

" Number of farmers including the treatment in their FPR trials

2) The number in brackets shows the number of farmers doing erosion trials in which the

variety is included

As in the first year all experimental activities were done by the participating farmers.

Project staff acted as coordinators and provided materials for the experiments. In

Ringinrejo all participating farmers used 5000 kg manure/ha and applied 300-375 kg

urea, 150-200 kg TSP and 100 KCl/ha in all treatments.

The yield and income of each treatment tested by participating farmers are given in

Table 7. Due to high variability between farmers' fields in the eroison trials, a valid

comparison between treatments is difficult. From the variety trials it can be concluded

(Table 7) that the two introduced varieties, 15/10 and SM-4772, have a good prospect.

To discuss the results and obtain the views of the participating farmers, field days

were held on August 15, 1996 in Sumbersuko and on September 19, 1996 in Renginrejo.

In addition to the participating farmers, some neighbor farmers were also invited and

participated in these field days. Farmers discussed the experimental results as well as the

future of the project. For the third year, there will be 22 farmers in Ringinrejo and 15

farmers in Sumbersuko participating in the project, testing some selected technologies in

their own fields.

481

Table 7. Average yields of cassava and maize as well as farmers' net income in nine

FPR erosion and six variety trials conducted by farmers in Ringinrejo in

1995/96.

Treatment Yield(t/ha)

1. Erosion control trials:

a. Gliricidia strips(Faroka)11

b. Gliricidia strips(15/10)

c. Gliricidia strips(SM-4772)

d. Calliandra strips(Faroka)

e. Calliandra strips( 15/ 10)

f. Flemingia strips(Faroka)

g. Leucaena strips(Faroka)

h. Elephant grass strips(Faroka)

i. Cowpea intercrop(Faroka)

J. No strips(Faroka)

k. No strips (Local/Ketela ijo)

2. Variety trials:

a. Faroka

b. 15/10

c. SM-4772

d. Local/Ketela ijo

Net income

(Rp/ha/year)Cassava Maize

5.6 1.1 1,387

8.9 0.6 868

9.0 0.7 731

6.3 2.2 2,453

8.2 1.5 791

5.6 0.9 1,191

2.2 0.8 707

3.4 0.9 1,052

1.5 0.6 520

4.9 1.2 1,778

5.5 1.0 1,307

4.2 1.1 1,075

9.4 1.0 1,238

5.1 0.8 1,084

5.2 1.2 581

"Cassava variety used in treatment

REFERENCES

Fujisaka, S. 1989. A method for farmer participatory research and technology transfer: Upland

soil conservation in the Philippines. Expt. Agric. 25:423-453.

Fujisaka, S. 1991. Improving productivity of an upland rice and maize system: Farmer cropping

choices or researcher cropping pattern trapezoids. Exp. Agric. 27:253-261.

Henry, G. 1994. Importance of the user perspective in agricultural research. Sasakawa Project

FPR Workshop, held in Rayong, Thailand. July 24-30, 1994.

Henry, G. and L.A. Hernandez. 1994. FPR case study: Cassava variety selection in Colombia's

North Coast. Sasakawa Project FPR Workshop, held in Rayong, Thailand. July 24-30, 1994.

Saragih, L. and S.M.H. Tampubolon. 1991. Integrated field level participatory policy to

promote soil and water conservation programs and project. Soil and Water Conservation of

Indonesia. Solo, Indonesia.

Utomo, W.H, 1994. Factors Influencing Soil Conservation Technology. Research Report.

Dept. of Education, Brawijaya University, Malang, Jakarta, Indonesia. (in Indonesian)

482

FARMERS' PARTICIPATION IN CASSAVA TECHNOLOGY TRANSFER

IN THE PHILIPPINES

Editha A. Gundaya and Fernando A. Evangelio1

ABSTRACT

Experiences gained from past root crop extension activities made PRCRTC realize the

importance of clienteles. participation in technology development and transfer. PRCRTC is now

trying to adopt a participatory approach in all cassava technology transfer activities. Results of

some of these extension activities shows that farmers. involvement in technology testing and

modification and in the over-all decision making process of a project, led to the development of

technologies that are better suited to the needs of the clienteles and helps to build up their capacity

to manage the project on their own.

In 1996 a project was initiated that employs farmer participatory research (FPR)

methodologies to transfer soil and water conservation technologies to cassava farmers in Bontoc,

south Leyte. This is a cassava growing area where cassava production is increasing due to the

establishment of a cassava-based feedmill, as well as the entry of San Miguel Corporation, which

buys large volumes of dried cassava chips for export. A preliminary survey about the farmers'

knowledge, attitude and practices concerning soil conservation has already been conducted with

91 cassava farmers as respondents. The majority (75%) of the farmers realized the damage that

would occur on continuously cultivating hilly areas, but only less than 50% are actually trying to

control erosion using various methods they learned from different sources. Around 65% of the

respondents, however, expressed their interest in learning soil conservation methods that would

be more effective than the methods presently used. The information given by the farmers is now

used as the basis for conducting other FPR activities in Bontoc.

INTRODUCTION

The increasing interest in cassava by the business sector offers opportunities to

further the development of the cassava industry in the Philippines. At present, the crop

is used not only as food by many Filipinos, but also as raw material in the manufacture

of several commercial and industrial products, like chips for export, starch, adhesives,

binders, feed and various food products. Some private companies are also looking into

the possibility of using cassava as raw material in the massive production of alcohol,

glucose and sorbitol.

Despite these opportunities, the cassava industry in the country has been growing

slower than what is desired, because it has been hindered by several problems. These

problems include low crop yield, poor processing facilities, low product quality, low

product price and lack of domestic markets.

The Philippine Root Crops Research and Training Center (PRCRTC) has been

supporting the cassava industry in the country through the development and transfer of

cassava technologies, such as high-yielding cassava varieties, improved cultural

1 Philippine Root Crops Research and Training Center (PRCRTC), Visayas State College of

Agriculture, Baybay, Leyte, Philippines.

483

management practices, cassava storage technologies, processing machines, feeds and

different food products. However, the Center's past extension activities had limited

impact on the cassava industry, especially on farmers. Acceptance of the technologies

introduced was rather low and sustainability of technology adoption, especially among

farmers and small processors, was hardly obtained.

Several factors caused these problems. One is too much focus on the technology

itself, disregarding other factors that greatly influence technology adoption, such as

market, the entrepreneurial and organizational capabilities of the technology users and

others. Another constraint was the farmers' lack of participation in the technology

development and transfer process. Farmers' participation was limited to being mere

recipients of the technologies developed by the research institutions, respondents in some

baseline surveys, participants in some formal consultation meetings, or cooperators of

some on-farm trials, which were basically designed by the researchers. According to

Werner (1993), nobody has a better understanding of his different needs and the

opportunities his farm offers than the farmer himself. Thus, the farmers' lack of

participation in the technology development and transfer process often resulted in

technologies that did not correspond with their needs and conditions.

With these realizations, PRCRTC is now trying to improve its technology

transfer approaches. Efforts are geared towards improving farmers' participation in the

technology development and transfer process. PRCRTC is also trying to incorporate

market development, organizational/entrepreneurial build-up, linkage establishment and

other neccessary components in the Center's technology transfer efforts. All these are

being considered in the PRCRTC's current cassava technology tranfer program (funded

by PCARRD-DOST), which focus on the expansion of cassava markets through the

establishment of integrated cassava projects.

This paper will discuss how the farmers are being involved in the implementation

of PRCRTC's cassava technology transfer projects in northern Mindanao and in Bontoc,

southern Leyte. This will also present the problems encountered and the possible ways

of increasing farmers' participation and/or improving the efficiency of project

implementation. Moreover, this paper will present the status of the FPR project on soil

and water conservation, which PRCRTC has started to conduct late this year as part of

its integrated cassava project in Bontoc, southern Leyte.

Direction of PRCRTC's Current Cassava Technology Transfer Activities

Considering the present status of the cassava industry in the country, PRCRTC's

cassava extension activities are geared towards: 1. improving the farmers' cassava

production level and processing efficiency in areas with existing cassava markets; and 2.

promoting cassava commercialization/market expansion in cassava growing areas which

are far from the existing cassava industries to encourage farmers to improve their cassava

production level and enable them to increase their incomes.

484

PRCRTC's Ongoing Cassava Technology Transfer Activities

The Center currently focuses its technology transfer activities in northern

Mindanao and the Visayas. The work in northern Mindanao is done to help the cassava

farmers improve their cassava production level and chips processing efficiency. The

project in the Visayas, on the other hand, are intended to expand the market for cassava

through the establishment of integrated cassava projects that can create sustainable

livelihood opportunities for the people. PRCRTC is currently assisting three integrated

cassava projects in the Visayas. Of these three projects, the Integrated Cassava-Feedmill-

Livestock Project in Bontoc, southern Leyte, was established first and is already

operational. Thus, the discussion of PRCRTC's experience in involving farmers in

technology transfer in the Visayas will be based on the Bontoc experience.

Farmers' Participation of the PRCRTC's Cassava Technology Transfer Activities

The cassava technology transfer projects in northern Mindano and in Bontoc,

southern Leyte, are implemented by multidisciplinary action teams and in coordination

with several agencies, i.e. the Department of Agriculture, Land Bank of the Philippines,

Department of Science and Technology, etc. Phasing of activities for each area differed

due to the differences in the nature of their problems and concerns. However, the

activities followed the same pattern of: 1. micro-level diagnostics (analysis of problems

and identification of possible solutions); 2. identification of project intervention and

technologies to be introduced; 3. identification of technology transfer strategies to be

used; 4. drawing up of detailed implementation plans; 5. actual project

implementation/technology transfer; and 6. monitoring and evaluation.

In the first four stages, farmers' participation was made possible through joint

visits and appraisals of the project sites, consultation meetings, and formal and informal

group discussions. *

In the actual project implementation/technology transfer, the farmers were asked

to participate in the following activities: 1. establishment of demonstration farms; 2.

trainings; 3. consultation meetings; 4. evaluation of the chipping machines; and 5. the

conduct of simple experiments.

The farmers participation in the different technology transfer activities are

further explained based on the experiences in the implementation of the projects in

northern Mindanao and in Bontoc.

I. Cassava Technology Transfer in Northern Mindanao

Background information

Northern Mindanao is one of the most important cassava producing regions in

the country. It is presently the site of rapid expansion of cassava production area due to

the presence of a number of starch mills and the increasing chip export activities by some

big companies, like San Miguel Corporation (SMC), CAPICAOR and GUANI

485

Marketing. In fact, financial assistance for the growing of cassava has been made

available by CAPICOR, the Land Bank of the Philippines, and recently by the SMC

Agribusiness Division.

Results of the diagnostic surveys revealed that despite these developments many

farmers are still complaining about having low income from cassava because of the low

yield of their native varieties and the low price offered by the chips exporters. They also

complain about the absence of processing machines that can improve their processing

efficiency and the quality of their chips. The exporters, on the other hand, are also

complaining that the dried cassava chips produced by the small cassava farmers/

processors do not meet the required quality of the importing firms in Europe, resulting

in high price discounts imposed on a number of their deliveries.

The above situation led PRCRTC to implement an action project that would

deliver the needed package of assistance/technology to the people in the area to make

cassava production and processing profitable for the farmers and at the same time

improve the quality and acceptability of dried chips. The technologies introduced to the

farmers include high yielding cassava varieties, improved cultural management practices

and chipping machines.

In the conduct of the different technology transfer activities, PRCRTC worked

with San Miguel Corporation, which had earlier sought the Center's assistance in looking

for cassava suppliers, and with other support agencies.

During the consultation meetings with the different agencies concerned, it was

agreed that SMC would do the legworking and the organization of farmers, Land Bank

of the Philippines (LBP) would be tapped to finance the cassava production activities of

the farmers, while PRCRTC would provide the needed technical assistance in the

propagation of planting materials of the recommended high-yielding cassava varieties,

training farmers on the improved cassava cultural practices and chips processing, and in

the fabrication of the needed chipping machines.

The farmers, on the other hand, were asked to participate in the establishment

and management of demonstration/model farms, technical training activities on cassava

production and processing, and in the testing/evaluation and possible modifications of the

chipping machines.

Establishment of model farms

To enable the farmers to actually observe the advantages of the high yielding

varieties and the improved cultural practices, and to have propagation areas for the

recommended high yielding cassava varieties, ten model farms (1.0 ha/site) were

established in strategic sites in Misamis Oriental, Bukidnon and Lanao provinces. These

model farms were managed by farmers; PRCRTC only provided the needed technical

supervision. Lakan, Golden Yellow, VC varieties (1 to 5) and other high-yielding lines

were planted in the model farms. The farmers' native varieties and their usual cassava

486

cultural management practices were used as the control treatment. Selection of the best

performing varieties were later conducted jointly by the farmers, the PRCRTC staff and

San Miguel technicians. Other cassava farmers were also asked to participate in the

selection process.

Farmers liked all the recommended varieties as these gave yields which were

higher than those of their native varieties. Considering chips recovery, Lakan and

Golden Yellow were choosen by the farmers because of their high dry matter content and

high chips recovery.

Training on cassava production and chips processing

To reinforce the knowledge gained by the farmers from the demonstration farms,

training on cassava production and chips processing was also conducted by technical

experts from VISCA.

Fabrication and testing of chipping machines

To support the chips processing activities of the farmers, SMC is currently

fabricating 15 units of pedal-operated chippers using the PRCRTC design. These

machines will be distributed to the farmers for field evaluation and for actual use by

farmers if found acceptable. SMC also plans to produce motorized chippers using the

PRCRTC design.

Project status

As of 1996, the total cassava expansion area in the three sites already reached

3,000 ha. Although all farmers liked the recommended varieties included in the model

farms, Lakan, Golden Yellow and VC-5 were used in the initial cassava production

expansion because planting material of these varieties was more readily available.

In the farms that use the recommended varieties and the management practices

recommended by PRCRTC, the average cassava yield ranged from 24-40 t/ha. Before

the introduction of the PRCRTC technology, the farmers were planting native varieties

which only gave them an average yield of 6-8 t/ha. Moreover, the chips processing

efficiency of the farmers is already improving with the use of the chippers provided by

SMC. However, a farmers' evaluation of the field performance and life span of the

machines still needs to be done.

II. Cassava Technology Transfer in Bontoc, Southern Leyte


Results of the micro-level diagnostics conducted in Bontoc revealed that the

municipality had a big unutilized hilly area suited for cassava production. Upland

farmers were growing cassava because it was one of the few food crops that could thrive

under the marginal conditions of the hilly area. However, the crop was grown only in

487

small patches not exceeding 0.25 ha. This was because cassava utilization in the area

was limited to food as a supplement for rice or maize, as animal feed, or was sold as

fresh roots to the markets in the neighboring towns. The farmers did not process the

crop into chips or other products.

The average yield of cassava in the area was low (3-5 t/ha). Many farmers were

using native varieties like Imelda, Pulutan, Makan and others.

Regarding livestock raising activities, it was found that the animals raised by the

farmers include carabao and native pigs and chicken. Only very few farmers raised cattle

and hybrid pigs. The other farmers said piglets of hybrid pigs were expensive and not

readily available in the area. The meat demand in Bontoc and the neighboring towns,

however, was high. This demand was satisfied by importing pigs from Davao.

The overall situation of the cassava production and animal raising activities in

Bontoc offered some opportunities for the development of integrated projects involving

the improvement of cassava production, establishment of cassava processing projects to

expand utilization and markets for the crop, and the development of the swine industry.

The technologies and expertise needed for the establishment of these projects were

available at PRCRTC-ViSCA.

A series of consultation meetings with the cooperator, a big cooperative known

as the Bontoc Multipurpose Cooperative (BCCI), were conducted to identify the specific

projects to be implemented in Bontoc. The BCCI and PRCRTC representatives later

decided to initiate an integrated project having the following components: 1 . cassava

production and chips processing; 2. cassava-based feedmill; and 3. pig (100-sow level)

and poultry raising.

The general concept of the project was that the farmer-members of BCCI would

be taught to improve their production level by planting high-yielding cassava varieties

recommended by PRCRTC. They would also be taught how to process cassavas into

dried chips using the PRCRTC-developed chippers. To serve as the main market of the

farmers' chips, a cassava-based feedmill would be established. The piggery and poultry

projects would serve as sure markets for the feeds produced by the feedmill. The

piggery and poultry projects were also envisioned to satisfy the demand for meat by the

people in Bontoc and the neighboring towns in southern Leyte. The cassava farmers

would be encouraged to regularly supply dried chips to the feedmill to keep it operating.

In short, the integrated project had been conceived to generate employment and increase

the farmers' income from cassava production.

Cassava production and processing

These components of the integrated project were established first to assure that

the feedmill would have a continuous supply of cassava chips once it started operation.

The introduction/transfer of the high yielding varieties, the improved cassava cultural

practices and the chipping machines was done through the establishment of demonstration

488

farms, training, and fabrication and evaluation of the chipping machines.

Demonstrationfarms

To showcase the cassava production technology developed by PRCRTC, a

demonstration farm containing the PRCRTC recommended varieties (Golden Yellow,

Lakan and the edible VC varieties) was set up in Bontoc. The demo farm, which was

managed by a farmer, was intended not only to show the farmers the advantages of

using the new varieties and the improved cultural practices, but also to propagate cassava

planting materials, which would be used by the farmers in their cassava production

activities.

Evaluation of the advantages of the improved cassava production practices were

later conducted by the farmers together with the PRCRTC and BCCI staff. The

performance of cassava in the demo farm was compared with cassava in the farmer's

field (using native varieties and traditional practices). The farmers observed that the

high-yielding varieties grown using the recommended practices had yields which were

more than twice the yield of the native varieties.

Training

To reinforce the knowlege gained by the farmers from the demo farm, PRCRTC

also conducted training activities on "Cassava Production" and "Chips Processing"

Farmers and technicians participated in these training activities. During the training, the

farmers were taught about the high-yielding cassava varieties, the improved cultural

practices for cassava, and the procedures in processing dried cassava chips, including the

use of the PRCRTC-developed chippers. The farmers expressed their apprehension about

the profitability of processing dried chips from cassava. After the discussion on the cost

and returns of chips processing, most participants were convinced to produce and process

cassava into chips for the BCCI feedmill.

Cassava Production

To identify farmer-cooperators for the cassava production and processing project,

the BCCI officials together with the PRCRTC staff met with the BCCI farmer-members

to inform them about the integrated cassava project. Several farmers expressed their

interest in participating in the cassava production and processing components of the

integrated project. The farmers, however, expressed their concern about the lack of

capital to expand their cassava production areas. Thus, BCCI decided to extend cassava

production loans to their members. The loanable amount was set at P6,000 per hectare.

Fabrication and Testing of Chipping Machines

To facilitate the cassava chipping operations, PRCRTC introduced to BCCI the

pedal-operated chipper which could chip 400-500 kg of cassava roots per hour. BCCI

489

ordered eight of these machines from PRCRTC. Construction expenses were shouldered

by BCCI. The machines were stationed in strategic places in the cassava-growing village

in Bontoc. The farmers took turns in using the machines at a minimal fee for

maintenance purposes. Farmers' initial feedback about the machines was positive. They

said the machines were many times more efficient than the bolo or knife. However,

some problems regarding the machines may occur later. Thus, long-term evaluation of

the machines' field performance and life span will have to be conducted by the project

staff together with the farmer-processors.

Feedmill establishment

Building construction and equipment acquisition

The feedmill was established after the farmers assured BCCI of their full support

through a constant supply of cassava chips. The building, which cost P800,000 was

constructed using BCCI's own money. The feedmill equipment, on the other hand, was

acquired by BCCI through DOST's financial support (loan grant).

Training on feedformulation

BCCI members who were identified to manage the feedmill component of the

integrated project were trained by PRCRTC-ViSCA on the formulation of cassava-based

feeds and on feedmill management. Hands-on training was done at the ViSCA Feedmill.

Piggery establishment

Construction of the BCCI' piggery was also done simultaneously with the

construction of the feedmill building. Financing came from the Development Bank of

the Philippines (P 2.5 million) and from the Land Bank of the Philippines-Maasin branch

(P 1.2 million).

Status of the Bontoc Project

Cassava Production

The status of BCCI's cassava production project as of the 1995/96 cropping

season is summarized in Table 1. There were 52 farmers who participated in the BCCI's

cassava production program. All availed themselves of the loan extended by the

cooperative. These farmers planted cassava before, but only in an area of less than 0.25

ha. When BCCI started its integrated cassava program, these farmers increased the size

of the area planted to cassava to not less than one ha. The total area planted to cassava

by the BCCI farmer-members who availed themselves of the cassava loan was 64 ha. The

varieties used were Golden Yellow and Lakan because according to them, these varieties

had high chips recovery and dried at a shorter period of time.

Yield sampling from different farmers' fields were conducted by the farmers and

the PRCRTC staff to determine the average yield of the cassava planted using the

490

recommended cultural practices. The average yield of the Golden Yellow and Lakan

varieties was 20 t/ha. This is already a very big improvement over the yields of the

native varieties (3-5 t/ha).

Chips Processing

A total of eight pedal chippers are currently used by the farmers to process chips

for the feedmill. According to the farmers, these units are not enough, especially during

the peak harvest season when many of them would like to use the machines. They also

reported that the chipper blades will not last long if used to process big and over-mature

roots. BCCI ordered chipper blades from PRCRTC to replace the destroyed ones. The

PRCRTC project staff delivered the needed blades but they plan to train some BCCI staff

on the repair and maintenance of the processing machines so that they would not have

to rely anymore on the Center if repairs are needed.

Another problem reported by the farmers in relation to their chipping operations

is the difficulty of drying the chips due to unpredictable weather and the lack of drying

areas. Solution to this problem still needs to be discussed among the project participants.

Table 1. Cassava production status before and during the implementation of the

BCCI cassava project in Bontoc, southern Leyte, Philippines.

When Project

Before was implemented

BCCI (1995/96 cropping

Parameter Project season)

Number of participating farmers

(BCCI members)

Total area planted to cassava (ha) under the

BCCI cassava program

Varieties used

Average area planted per

farmer (ha)

Average yield (t/ha)

52

64

Imelda, Golden Yellow

Makan, Lakan

Pulutan

0.25 1.0

3-5 20

491

Chips Marketing

The chips processed by the BCCI members were bought by BCCI at P3.00/kg

(farm gate price) for the cassava-based feedmill. From Feb 1996 (when the BCCI

feedmill started operating) to Sept 1996, BCCI was able to buy a total of approximately

200 tons of chips from its farmer members. About 61 % of these chips have been used

by BCCI for the formulation of cassava-based feeds, while the remaining 39% have been

sold at P4.00/kg to other chip users, like the ViSCA Feedmill, Biliran Feedmill, Placer

Feedmill and the San Miguel Corporation.

Forty one farmer-cooperators have already sold cassava chips to BCCI (at

P3.00/kg). During a survey conducted in the middle of 1996, 38 farmer-cooperators

claimed to have benefitted from the venture, while 13 did not mention any specific

benefit (Table 2). Among the benefits mentioned were higher profit and the availability

of money to buy better food (rice and others), pay debts, pay children's school fees and

buy medicine. However, when asked about the specific amount of the profit, only 19

farmers were able to give figures, the other 22 said they did not keep records of their

expenses and profits. The profits reported ranged from PI,000 to PI 0,000 per hectare

(Table 3). It was observed, however, that those who reported higher profit were those

who maintained the cleanliness of their farms and followed most of the recommended

cassava cultural practices.

Table 2. Benefits derived by BCCI farmer cooperators from processing and selling

of dried cassava chips to BCCI (n = 41) in Bontoc, southern Leyte,

Philippines.

Benefits Frequency

Big profit 4

Helped to buy better food 1 1

Helped during hardships (buy medicine, pay debts

pay children's school fees) 13

No response 13

Feedmill operation

Feedmill operations formally started in Feb 1996. The cassava-based feed

formulations produced include pig starter, pig grower and pig finisher feeds. The

feedmill is currently supplying cassava-based feeds not only to the BCCI's piggery but

also to the other swine raisers in the municipality and the other neighboring towns. The

492

BCCI's major feed markets, aside from its own piggery, are its members in Bontoc,

Liloan, Malitbog and Sogod. These people can buy feed at cheaper prices (8% mark

up) than non-members (10% mark-up).

Per suggestion of the PRCRTC staff, the coop management is currently hiring new

staff to take charge of the marketing of feeds. This staff will be responsible for planning

the appropriate marketing strategies to increase the sales of the cassava-based feeds.

PRCRTC-ViSCA, will assist in market development through the production of

promotional materials, i.e. brochures/leaflets and posters on the proper use and

advantages of cassava-based feeds.

Table 3. Amount of profit derived from chips processing and selling activities (n=41)

in Bontoc, Southern Leyte, Philippines.

Profit Range" Frequency

P 1,000 -P 5,000 16

P 6,000 - P 10,000 3

Cannot estimate/no record 22

Total 41

" 1 US$ is approx. 25 pesos

BCCI Piggery

The piggery building was completed in Jan 1996. At present it has four boars

(Duroc and Large White) and 60 sows (Large White and Hypor) most of which are

pregnant. Additional animals will be procured early next year.

Evaluation of the cassava-based feeds' effect on the performance of the animals i.e.

weight gain, carcass quality, etc., still needs to be done.

III. FPR on Soil and Water Conservation in Bontoc


With the ongoing processing and marketing activities in northen Mindanao and

Bontoc, there is a great possibility that the cassava production areas in the two sites will

expand. In Bontoc, BCCI has been urged by SMC to become one of its cassava chips

suppliers. The BCCI staff who manages the cassava project, however, said that at this

time, they are apprehensive to enter into an agreement with San Miguel because even at

493

the present scale of the integrated project, BCCI has already encountered some difficulties

in the project. But even if SMC will not enter into the picture, there is still a great

possibility for area expansion because the farmers are opening more hilly areas to plant

cassava for the BCCI feedmill.

A positive development which would promote the expansion of cassava production

in Bontoc is the DA-LGU's grant of a tractor to BCCI to support cassava production.

The tractor is now ready for use. The Department of Agriculture (DA) and BCCI will

make a memorandum of agreement regarding the use of the tractor by the BCCI members

(especially on rentals).

In anticipation of the opening of so much hilly areas for cassava production, the

PRCRTC and DA staff and the BCCI officers and members, during the consultative

meeting held in June 1996, agreed on the importance of introducing soil and water

conservation (SWC) technologies to the cassava farmers.

Preliminary survey.

A survey with 91 farmer-respondents was conducted in the cassava-growing

villages in Bontoc to monitor the initial results of the integrated cassava project and to

gather initial information about SWC practices among the farmers in the area. Of the 91

farmers respondents, 75% realized the damage that would occur in continuously

cultivating hilly areas due to soil erosion. However, only 50% were trying to control

soil erosion using their own methods, i.e. plowing deep along the contours or fallowing.

Nevertheless, 60% of the respondents were interested to learn SWC techniques that are

more effective than their present practice.

In line with PRCRTC's current efforts to encourage farmers' participation in

technology development and transfer, the project staff will be transfering soil and water

conservation technologies to the farmers in Bontoc using the FPR approach. A formal

survey will still need to be conducted to gather more information needed for the planning

and implementation of the FPR activities.

Establishment of demonstration farms.

An erosion control trial established earlier by PRCRTC in a village near ViSCA

does not exist anymore because the owner need the land back for other purposes. Thus,

PRCRTC is now planning to set up demo plots showing the different SWC techniques

in Bontoc. However, several arrangements have to be made before these demo plots can

be established.

In the meantime, two one-hectare cassava demo farms using vetiver grass as

contour hedgerows have been established in Feb 1996. One demo farm was set up in a

moderately sloping cassava farm in Pamahawan village, while the other was set up in a

steeper farm in Mahayahay village. As of Oct 1996, the vetiver grass hedgerows in the

two demo farms had 100% survival.

494

CONCLUSIONS

In general, the cassava-based projects in northern Mindanao and Bontoc still need

to be strengthened. A lot of activities, like the expansion of area planted to cassava,

protecting the cassava area from destruction through appropriate soil and water

conservation techniques, strengthening market linkages for chips, promotion of the

cassava-based feeds (in the case of Bontoc), and other related activities have to be

continued. However, preliminary results show that the projects have already provided

some benefits to the intended clienteles. In northern Mindanao, the use of high-yielding

varieties and the improved cultural practices increased the yield of cassava from 6-8 t/ha

to 24-40 t/ha. Also, the introduction of the chipping machines improved the chips

processing efficiency of the farmers.

For the upland cassava farmers in Bontoc, the cassava production and chips

processing activities enabled them to earn considerable profits, which they used to buy

better food and medicine and to pay some of their financial obligations. The cassava

chips trading activity of BCCI added income to the cooperative. Some of the swine

raisers in the area were also able to buy cheaper but good quality feeds from the BCCI

feedmill.

Several factors contributed to the initial success of these projects. One is the

farmers' involvement in all phases of project implementation.

Some Observable Results of Farmers Participation in Technology Transfer Activities

As a result of the increased farmers' participation in the technology transfer

process, the following happened:

1. Identification of real farmers' problems, i.e. lack of cassava markets for the farmers

in Bontoc; and low yield, low chip prices and lack of processing machines for the

farmers in northern Mindanao.

2. Identification of solutions/project interventions that would likely fit their conditions,

i.e. implementation of an integrated project that created additional markets for cassava

in Bontoc; and the introduction of high-yielding varieties and chips processing machines

acceptable to farmers in northen Mindanao.

3. Awareness of the opportunities offered by cassava, i.e. other uses aside from food.

4. Farmers' increasing participation in project activities, i.e. as suppliers of cassava chips

to the feedmill and buyers of feeds from the same feedmill.

5. Feeling of "ownership" by the farmers for their project, i.e. the BCCI feedmill and

piggery.

6. Identification of other activities/technology modifications that need to be done, such

as FPR in soil and water conservation in Bontoc.

Problems in the Implementation of Integrated/Participatory Cassava Projects

Despite the positive results of farmers' participation in the cassava technology

495

transfer projects, the following problems were encountered:

1. Coordination among support agencies. The Center, being the lead agency in the

conduct of integrated cassava projects, was not able to form a cassava council to oversee

the different project activities before project implementation. As a result, the Center staff

found it difficult to obtain maximum participation among the different agencies involved

in the project. Some targets were not reached because the other agencies were not able

to do their parts owing to conflicts with their other responsibilities and priorities.

2. Scale of integrated project is too big for the cooperators. This is true in the Bontoc

project. The people in charge of the different project components found the scope of the

project too big. They said they could not manage the project if they have to go into

cassava area expansion to serve the needs of San Miguel for cassava chips. They said

they have to concentrate on solving the problems of the feedmill and livestock projects

before they can expand their cassava production to serve the needs of SMC.

3. Lack of capability of the cooperator to handle integrated projects. This could be the

reason why the people in charge claimed that the integrated project is too big. The

project manager is afraid to take business risks, especially if one has to talk about project

expansion. He said he lacks the capability to manage the complexities of the integrated

project.

4. Lack of staff to closely monitor the projects. The Center's extension division is

generally understaffed. This is the reason why it could not always monitor the activities

and solve the problems of the projects. Some technical problems are not addressed right

away, such as the problem of lack of dryers.

Possible Ways to Improve PRCRTC's Implementation of the Cassava Technology

Transfer Activities

The following suggestions made by Perez-Crespo (1991) can be used to improve

the implementation of the cassava technology transfer projects undertaken by PRCRTC:

1 . Formal organization of a council to support the implementation of the integrated

cassava project in Bontoc. The council should be composed of technology generators

from PRCRTC-ViSCA, extension workers from PRCRTC-ViSCA and other government

agencies offering support to the project, rural development program administrators (LGU

officials) and farmers.

2. Keep the integrated project small and simple at first to avoid confusion and to allow

the cooperators to learn first about the details of the project before expanding into other

ventures.

3. The project should concentrate on giving those aspects direct benefits to farmers. This

means that the project should be able to increase the income of the farmers and improve

their living conditions. In the case of Bontoc, the project should make sure that the

farmers can gain from their cassava production and chips processing venture.

4. Involve farmers in the conduct of small experiments such as FPR on soil and water

496

conservation. This will increase the farmers understanding of the technologies introduced

and the likelihood that the technologies will fit the conditions of the farmers, and thus,

be adopted on a sustainable basis.

REFERENCES

Perez-Crespo, C.A. 1991. Integrated Cassava Projects. CIAT, Cali, Colombia. 242 p.

Gundaya, E.A., F.A. Evangelio, R.T. Sanico, J.R. Roa, R.R. Orias and M.C.U. Ramirez. 1995.

Cassava technology transfer in the Philippines. In: R.H. Howeler (Ed.) Cassava Breeding,

Agronomy Research and Technology Transfer in Asia. Proc. 4th Regional Workshop held in

Trivandrum, India. Nov. 2-6, 1993. pp. 322-336.

Werner, J. 1993. Participatory Development of Agicultural Innovations: Procedures and Methods

of On-Farm Research. GTZ, Eschborn, Germany. 251 p.

497

FARMER PARTICIPATORY RESEARCH FOR CASSAVA TECHNOLOGY

TRANSFER IN ASIA - CONSTRAINTS AND OPPORTUNITIES

Reinhardt H. Howeler1 and Guy Henry2

ABSTRACT

Since 1994 a farmer participatory research (FPR) methodology has been used with the

objective of enhancing the development and adoption of efficient cassava production practices that

will reduce erosion, maintain soil productivity and increase the income of cassava farmers in Asia.

This 5-year FPR project, funded by the Nippon Foundation in Japan and coordinated by CIAT,

is being executed by national research and extension organizations in Thailand, Indonesia, China

and Vietnam. Members of the FPR teams in each of these countries participated in a Workshop

in July 1994 in Thailand to become familiar with the FPR philosophy and methodologies. Upon

return, they conducted Rapid Rural Appraisals (RRA) in cassava growing regions in their country

to select two suitable pilot sites for the project. In addition, they established demonstration plots

to show the farmers of the pilot sites a range of management practices to control erosion and

increase yield or income. During a field day farmers looked at and discussed the various options

and selected 4-5 that were considered most useful for their own conditions in order to try these

on their own farms.

In 1995 the first FPR trials were set out by fanners on their own fields with help from

FPR team members. In erosion control trials they established 2-5 treatments on a uniform slope

and constructed sedimentation channels along the lower side of each plot to collect the eroded

sediments and measure soil losses due to erosion. In addition, other technology components such

as improved varieties, alternative intercrop systems and fertilizer treatments were offered and

experimented with by farmers. At the end of the first year, farmers and FPR team members

jointly harvested all the plots and calculated cassava and intercrop yields, as well as the amount

of soil loss in each treatment. These results were discussed with the participating farmers in order

to select the best treatments for the second year of testing in 1996.

From the experiences obtained so far we have learned that farmers in the selected sites are

interested in the trials, and are adapting and adopting several component technologies. However,

the success rate has been varied, especially between different sites and countries. A number of

limitations have been identified, both technical, financial, organizational and institutional.

This paper assesses the results of the project and identifies and analyzes the various

constraints that are currently limiting the project. In addition, new opportunities are proposed that

may alleviate the constraints. The analysis is conducted within a framework of how to move the

project from the pilot phase to an implementation phase in order to reach a wider audience and

obtain greater adoption of the developed technologies.

INTRODUCTION

Since 1987 the CIAT Cassava Agronomy Program in Asia has coordinated a

network of cassava agronomists in various countries in Asia. These national program

1 CIAT Asian Cassava Program, Dept. of Agriculture, Chatuchak, Bangkok.Thailand.

2 Economist, CIRAD-SAR, Proamyl, BP 5035, 34090 Montpellier, CEDEX 1, France;

formely CIAT Cassava Program, Apartado Aereo 67-13, Cali, Colombia.

498

scientists have conducted agronomy and soil management experiments in collaboration

with CIAT, with major emphasis on soil fertility maintenance and erosion control.

Results of these experiments are reported in this and in previous Workshop Proceedings.

From these experiments it was concluded that cassava can indeed cause soil nutrient

depletion if the crop is grown continuously without application of adequate amounts of

nutrients in the form of organic or chemical fertilizers, and that cassava cultivation on

slopes may cause serious erosion if the crop is not properly managed. However,

research has shown that erosion can be markedly reduced either by common agronomic

practices, such as minimum tillage, planting on contour ridges and at relatively close

spacing, fertilizer application and intercropping, or by special soil conservation measures,

such as application of mulch or the planting of contour barriers of grasses or legumes to

reduce raindrop impact on the soil and to slow water run-off down the slope. While

most of these practices were found to be effective in controlling erosion, very few

cassava farmers are actually using these practices, either because they are unaware of the

seriousness of soil erosion, or because they don't know which practice is most effective

or most suitable for their own conditions. Since most of these practices require some

additional labor or financial inputs, while the benefits tend to be long-term, farmers are

seldom interested in practicing soil conservation. From these and other experiences it

was concluded that cassava farmers will not adopt more sustainable management practices

unless they first become aware of the extent and long-term effect of soil erosion on soil

productivity; and secondly, they themselves test and select the most suitable practices

under their own conditions.

To enhance the adoption of more sustainable practices by cassava farmers in Asia,

a new special project, funded by the Nippon Foundation in Japan and executed by CIAT

in collaboration with national scientists, was initiated in 1994. The strategy to achieve

the objectives was to develop a Farmer Participatory Research (FPR) methodology for

testing soil management practices together with farmers in pilot sites in some important

cassava growing countries in Asia. Thus, two or more pilot sites were selected in

Thailand, Vietnam, Indonesia and China. Research and extension institutions dealing

with cassava were invited to join the project and to name an "FPR team" of agronomists

and social scientists to collaborate in its execution. In addition to the FPR project, the

same or other institutions continued the conducting of collaborative strategic or applied

research on cassava agronomic practices in order to identify still more effective

technology components to enhance productivity and reduce soil degradation.

FPR PROJECT

The various activities of the project include the following:

1 . Organize a consortium of collaborating research and extension institutions in each

of the four participating countries, and identify the persons that will be directly

involved in the project.

499

2. Conduct a one-week Workshop on FPR Methodologies with participation of the four

FPR teams.

3. Select potential pilot sites and conduct Rapid Rural Appraisals (RRA) in each site to

select at least two appropriate pilot sites in each country.

4. Establish in each country or site Demonstration Plots with a large range of

management options.

5. Organize a Farmers' Field Day at the Demonstration Plots to let farmers evaluate and

select the best technological options for their own conditions.

6. Select participating farmers and let them choose the type of FPR trials to be

conducted at each site and the treatments to be used in each type of trial.

7. Test, evaluate and select the most attractive options with farmers in their own fields.

This includes experimentation with practices to control erosion as well as with,

varieties, cropping systems and fertilization.

8. Through a reiterative process of trying out, discussing, selecting etc., develop the best

package of practices for sustainable cassava production in each site.

9. Try out the best practices in commercial fields.

10. Enhance the testing and adoption of these practices in nearby villages.

1. Collaborating Institutions

Table 1 list the various research and extension institutions collaborating in the

project. Beside agronomists or soil scientists, attempts were made to include economists

or other social scientists in the project. Local extensionists also played an important role

in Vietnam and China.

2. Training Workshop on FPR Methodologies

In order to become familiar with the FPR approach, FPR team members o*f the

collaborating institutes participated in a one-week Workshop, held in Rayong, Thailand,

from July 24 to 30, 1994. Besides lectures on the principles of FPR and some of the

methodologies used, participants developed a workplan for the project in each country

and also practiced interviewing cassava farmers, both in groups and individually.

3. Rapid Rural Appraisals (RRA)

Each FPR team conducted RRAs in potential pilot sites by interviewing farmers about

general farming conditions in the area, cassava production practices, problems and

constraints (including erosion), utilization and marketing. Based on these data, each team

selected two sites considered most suitable based on the following criteria

- cassava is and will most likely remain an important crop in the area

- cassava is grown on slopes

- erosion is a serious problem and is perceived as such by the farmers

- farmers are interested in participating in the project

500

Table 1. Institutions collaborating with CIAT in the Nippon Foundation Project

on Improving Agricultural Sustainability in Asia.

Country/Province Institution FPR project Research

China-Hainan

China-Guangxi

China-Guangdong

Indonesia-E.Java

Indonesia-E.Java

Indonesia-W.Java

Philippines-Leyte

Philippines-Bohol

Thailand-Bangkok

Tahiland-Bangkok

Thailand-Bangkok

Thailand-Korat

Vietnam-Thai Nguyen

Vietnam-Hanoi

Vietnam-Ho Chi Minh

Chinese Acad. Tropical Agric.

Sciences (CATAS) /

Guangxi Subtropical Crops

Research Institute (GSCRI)

Upland Crops Research Institute

(UCRI)

Brawijaya University (UNIBRAW) /

Research Institute for Legumes and

Tuber Crops (RILET) /

Bogor Research Institute for

Food Crops (BORIF)

Phil. Root Crops Research and

Training Center (PRCRTC)

Bohol Experiment Station (BES)

Field Crops Research Institute (FCRI)

of Dept. of Agriculture /

Field Crops Promotion Division

of Dept. Agric. Extension /

Kasetsart University

Thai Tapioca Development Institute /

Agro-Forestry College

of Thai Nguyen University /

National Soil and Fertilizer Institute

(NSFI) /

Institute of Agric. Sciences (IAS) of

South Vietnam

501

Detailed information obtained in each site have already been presented in earlier

papers (Zhang Weite et al., Wilawan Vongkasem et al., Nguyen The Dang et al., and

Wani Hadi Utomo et al.) in this Proceedings. Table 2 shows a comparative summary

of the RRA data collected in the pilot sites selected for the project. This shows that

cassava is an important crop in all sites, but is the most important crop in only two of

the eight sites. The cassava planted area per household is rather large in Thailand and

in Baisha county of Hainan, but very small in most other sites. Farm size is an important

determinant in the selection of suitable crops, cropping systems and production practices.

The relatively large farm size in Thailand, for example, necessitates partial mechanization

and almost precludes the use of intercropping systems.

4. Demonstration Plots

In each country FPR team members established demonstration plots with a large

number of treatments to be able to show farmers many technological options and their

effect on yield, total income, and erosion. Plots were laid out on a uniform slope; along

the lower end of each plot a ditch was dug and covered with plastic (Figure 1). Eroded

sediments and runoff water would collect in these sedimentation channels. Water was

allowed to seep away through small holes made in the plastic, and sediments were

collected and weighed several times during the cassava growth cycle. Samples of wet

sediments were taken to be dried and weighed in order to calculate soil losses per ha on

a dry weight basis. Results of cassava and intercrop yields, gross and net income, as

well as soil losses due to erosion in these demonstration plots are presented in earlier

papers (Zhang Weite et al., Wilawan Vongkasem et al., Nguyen The Dang et al., and

Wani Hadi Utomo et al.) in this Proceedings.

5. Farmers' Field Day

Shortly before or during the harvest of cassava, farmers from the selected pilot

sites were invited to visit the demonstration plots, with the objective of discussing the

pros and cons of each treatment and then to score the treatments in terms of general

usefulness, i.e. effectiveness in reducing erosion while maintaining or increasing farmers'

income. The occasion was also used to explain clearly the objectives of the project and

to inform farmers about new varieties and other new technologies.

Table 3 shows the ranking of management practices considered most useful by

farmers from seven pilot sites. The treatments in the demonstration plots varied from

country to country, but even within the same country farmers' preference varied from site

to site. However, in both Thailand and Vietnam, farmers liked the treatment of vetiver

grass barriers and decided to try this as one of their treatments in the FPR erosion control

trials. In Indonesia, farmers generally preferred intercropping cassava with maize (their

traditional practice) and planting Gliricidia sepium or elephant grass as contour barriers,

as both can be used as animal feed.

502

6. Selection of Participating Farmers and Treatments for FPR Trials

In most cases there was no particular selection of farmers to participate in the

project, i.e. those farmers that were interested could participate. Farmers that had

sloping land suitable for erosion control trials were encouraged to do those trials, while

those with flat land participated in variety, fertilization or intercropping trials. Table 4

shows the types and number of trials conducted in each pilot site in 1995/96 and

1996/97.

In Baisha county of Hainan about 37 farmers participated in the first year. They

generally had only two treatments per trial, comparing an "improved" practice or variety

versus their traditional practice or variety. The large number of farmers participating

was difficult to manage, while having only two treatments per trial made it difficult to

compare among "improved" treatments. Thus, in the second year, the number of trials

in China was reduced while the number of treatments per trial was increased. Moreover,

farmers within one site were encouraged to all test the same 4-5 "improved" practices or

varieties versus their traditional practice or variety. This way, trial results could be

averaged over farms and more reliable results could be obtained to draw conclusions and

select the best treatments. In Vietnam the number of participating farmers increased in

the second year (1996/97) as farmers saw the benefits of participating in this community

effort, especially in obtaining planting material of new varieties.

Before starting the trials, participating farmers met in the village with the FPR

team members to discuss the type of trials to be conducted and the treatments to be

tested. For the erosion control trials farmers discussed the results of the scores given to

each treatment during the field day at the demonstration plots. They generally selected

3-4 treatments with high scores, but sometimes they themselves suggested new treatments

that seemed of greater benefit for their own particular circumstances. Thus, in Soeng

Saang district in Thailand, farmers wanted to test contour barriers of sugarcane (for

chewing) as a more useful alternative to king grass, which they had observed in the

demonstration plots. Also, some farmers raising silkworms wanted to test hedgerows of

mulberry bushes as a means to control erosion while also obtaining benefit from the

barrier. In Thailand farmers decided to test 3-4 common treatments as well as one

preferred individual treatment, all in comparison with their traditional practice. When

farmers test one individually selected treatment, They are encouraged to think for

themselves about effective ways to control erosion while at the same time providing

additional benefits or income. These farmer innovations can sometimes lead to better and

more practical management practices, and also enhances farmers' feelings of

empowerment to find their own solutions. This is a fundamental element for success

(Ashbyera/., 1997).

To compensate for the additional cost of doing the trials, farmers were paid for

503

digging the sedimentation channels and received the plastic for covering the channels.

They also received planting material of vetiver grass and new cassava varieties for the

trials, as well as seed for intercropping treatments. In Thailand farmers also received one

bag of 15-15-15 fertilizers, while in one site in Indonesia the participating farmers as a

group received 15 goats. These incentives were kept to a minimum to enhance the

feeling that farmers were conducting the trials for their own rather than for the

researchers' benefit.

7. Testing, Evaluation and Selection of Best Options

Once the types of trials as well as the treatments were selected, FPR team

members helped the farmers to select the most suitable site for each trial, to set out

contour lines (for the erosion control trials) and stake out the trials. Especially the first

year, team members had to help farmers establish the various treatments. But once

established, farmers managed their own trials similar to their other commercial fields.

Team members would visit regularly to discuss the progress and try to solve any

problems. They would also collect and weigh the eroded sediments in the sedimentation

channels, usually once during the cassava growth cycle and again at time of harvest.

A very common problem in the erosion control trials was that some trials were

not laid out well along contour lines, as most farmers would prefer their trials laid out

parallel to roads or the edge of fields. In that case, run-off water would sometimes enter

or leave plots through side borders, resulting in unreliable soil loss data. Moreover, if

the erosion trials were situated halfway or near the bottom of a slope, run-off water from

fields above would enter plots if the diversion ditches along the upper side of plots

(Figure 1) were unable to divert all the run-off away from the plots. In that case, large

amounts of run-off would enter the plots, causing excessive erosion that was not related

to the treatment. As such, the eroded sediments in the ditches did not accurately reflect

the effectiveness of the treatment in controlling erosion.

At time of harvest, participating farmers and FPR team members would jointly

harvest all or part (usually 16-20m2) of each plot to determine cassava root yield. In

Thailand, where farmers receive a differential price according to root starch content, the

starch content was also determined. In case of intercropping treatments, the yield of the

intercrops had been determined earlier at their time of harvest. During the cassava

harvest farmers also noted and discussed the amount of sediments in the ditch of each

treatment, before those sediments were collected and weighed.

One problem observed during the harvest in the first year was that farmers had

often planted at irregular spacings, making it very difficult to accurately determine

effective plot size and compare yields; in subsequent years farmers were encouraged to

use a standard planting distance, usually 1.0x1.0 m, 0.1x0.8 m or 0.8x0.8 m. Another

commonly observed problem in estimating yield in plots with contour hedgerows, was

that researchers often excluded from their harvested plot any rows bordering those

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hedgerows. As such, they ignored the fact that hedgerows occupy part of the land and

may either increase (mulching effect, trapping of water and fertilizer) or decrease

(competition effect) the yield of bordering cassava plants. To correct this problem,

harvested plots should include the hedgerows approximately in the same proportion they

might be found in commercial fields (usually about 10-20% of crop area, depending on

slope). On the other hand, if experimental plots have more than the necessary number

of hedgerows (usually spaced at 1 m vertical distance between hedges), crop yields are

likely to be reduced more than necessary, and farmers may unduly reject such treatments

for that reason. Finally, another common problem is that the "farmers' traditional

practice" treatment, used as comparison with other "improved" practices, does not reflect

actual farming practices. If this treatment is not "real", farmers may reject the results

of the whole trial as not accurate.

After all trials had been harvested and all data (including yields of intercrops and

hedgerows, eroded sediments, etc) collected, FPR team members quickly calculated and

tabulated the results, including the gross and net incomes obtained in each treatment,

expressed in local currency and units of measurement. These were then presented to and

discussed with the farmers. Farmers were asked to score treatments or raise hands for

those treatments they preferred, considering both the effectiveness in controlling erosion

and producing benefits (higher income or other benefits) to the farmers. In the same

meeting farmers were usually asked whether they liked to continue the FPR trials, which

types, and which treatments. Farmers usually selected the "best" treatments from the

previous cycle, sometimes combined with newly proposed treatments. Thus, "best-bet"

treatments were again tested against farmers' traditional practices in a reiterative process

to develop a package of management practices, including new varieties, optimum

fertilization, productive intercropping systems and possibly hedgerows or other special

measures to reduce erosion, that would optimize yields or income while reducing erosion

and soil nutrient depletion.

8. Trying out in Practice

Usually, after 2-3 years of experimentation in relatively small plots, farmers

would be convinced of the usefulness of certain practices, and would be ready to try

"their" recommended practices on their own production fields. These practices should

be tried for 1-2 years on a relatively small scale, such as 0.1-0.2 ha, to determine

whether these practices are truly practical and meeting farmers expectations. If not, they

may need to be tested again in a modified version that better corresponds with the

conditions in the field. Especially in Thailand, where commercial fields tend to be large,

some further modification may be necessary to facilitate mechanized land preparation and

harvesting.

509

CONSTRAINTS AND OPPORTUNITIES: WHAT HAVE WE LEARNED?

Table 5 shows a comparative summary of the conditions of the FPR trials

conducted in the eight pilot sites as well as some of the problem encountered. Specific

conditions at the site, the relation between the institutions involved in the project, as well

as their relation with local extensionists and village leaders, often have a strong bearing

on the success or failure of the project.

1. Conditions at the Pilot Sites

Table 5 summarizes some of the pertinent biophysical and socio-economic

conditions at the sites. Travel time from the participating institute to the sites varied

from less than one to more than five hours by car. Less time required to go to Pho Yen,

Luong Son or south Malang facilitated more frequent visits of FPR team members to

these sites. The longer distances in Thailand made frequent visits or long stays at the

sites impractical. To get the work done quickly and efficiently, the Thai FPR team often

brought their own laborers. While certainly efficient, this eliminated the need to involve

farmers directly in the work and thus reduced farmers' participation and interest.

Although in China the pilot site in Baisha county is only 1 1/2 hours from CATAS, the

lack of transport facilities as well as the lack of personnel at CATAS prevented regular

visits to that site. For the same reasons, attempts to expand to a second site in

Quongzhong county and later in Tunchang county were unsuccessful. Thus, distance to

and accessibility of the sites is another important criterion in selecting pilot sites.

Cassava was the principal crop only in Soeng Saang and in Malang, and an

important secondary crop in the other locations. The more important cassava is in the

whole cropping system, the more farmers will be interested in developing practices that

will optimize cassava yields and protect the soil's productivity. Similarly, the smaller

farm sizes (Table 2) in Vietnam and Indonesia result in more intensive land use

management and greater concern for maintaining soil productivity. Also, slopes were

quite steep in Thanh Hoa and Luong Son districts in Vietnam, in some areas of Baisha

county of China and in Malang district in Indonesia, resulting in serious soil losses due

to erosion. This enhanced farmers' concern about the problem. These three aspects

influence the degree of farmers' interest and participation in the project.

In most sites both men and women participated in the project, but for cultural

or religious reasons only men participated in Baisha county in China and in the two sites

in Indonesia. This did not seem to have any direct bearing on the interest of farmers or

their degree of participation. Of greater importance is the interest of the leaders in the

village or of local extensionists. In both sites in Thailand the village leaders were

supportive of and actively involved in the project; in Pho Yen in Vietnam and in Blitar

in Indonesia this was also the case, while in Baisha county in China a local extensionist

510

was providing good leadership to the project.

2. Institutional Relations

In Thailand the project was executed jointly by the Dept. of Agriculture (DOA)

and the Dept. of Agricultural Extension (DOAE). Teams from both institutions worked

together very effectively in both sites, the DOA providing research expertise and planting

material of new varieties, while DOAE provided expertise in extension activities as well

as access to a nationwide network of extension offices, which participated in various

degrees in the selection of sites, in the conducting of RRAs, and in the execution of the

FPR trials. In other countries each site was the responsibility of only one institute. This

facilitated decision making and management, but each institution did not benefit much

from the expertise or the experience obtained by the other institutes in the country. A

sharing of experiences and mutual participation in at least the final field day at harvest,

would probably have improved the project execution at some of the sites.

In Pho Yen district of Vietnam much of the responsibility for helping farmers

establish the trials and the taking of data rested with the local extension office, as well

as with 4th-year students from Agro-forestry College of Thai Nguyen University. These

students would live, or spend a considerably amount of time, with farmers in the village,

which stimulated mutual learning and contributed to a close relationship between farmers

and FPR team members. In Blitar district in Indonesia the project was similarly executed

by an MSc student who spent a lot of time in the village and build a good relationship

with the participating farmers. Where possible, this seems an effective way to improve

the quality of the trials and build trust between villagers and government officials.

3. Technical Problems

Technical problems in executing the FPR erosion control trials concerned mainly

the laying out of the trial along contour lines, preventing water from entering or leaving

the plots from fields above or through side borders, and the correct measurement of

yields, which should include the effect of contour hedgerows if present. These have

already been discussed above. An additional problem is that some plastics used in the

sedimentation channels deteriorated very quickly or were stolen. Attempts to substitute

plastic sheet with bamboo matting or opened-up plastic fertilizer bags were not very

successful. Lining sedimentation channels with split-open bamboo has been successful

in the Philippines, but this material is not readily available in other countries. Other

technical problems encountered include the poor germination of cassava stakes if they had

been stored for too long, and poor germination of some hedgerow or intercrop species

due to poor quality seed or unfavorable weather. Furthermore, results of FPR trials were

sometimes unreliable due to poor marking of plots, difficulty in calculating effective plot

size due to irregular cassava planting distances, varietal mixtures, poor weed control,

stealing of crops, and damage of cassava or intercrops by water buffaloes or rats.

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4. Availability of Attractive Options

One of the most important requirements for obtaining farmers' interest in the

project is the availability of new and attractive technological options. In most pilot sites

farmers were interested in participating not because of their concern for soil erosion, but

because of the possibility of obtaining planting material of new higher-yielding varieties.

Farmers were primarily interested in testing new varieties, new intercropping systems or

fertilizers, because all of these can directly increase their net income. Fortunately, in all

participating countries cassava breeders had already developed higher-yielding varieties,

which were ready for on-farm testing and distribution. In Indonesia, however, these

varieties were only marginally better than the local varieties, while in Vietnam and China

the lack of sufficient planting material of new varieties initially limited their use. Once

farmers saw the benefits of these new varieties, of better intercropping practices and of

correct fertilizer use, they became more enthusiastic about the project, including the

development of practices to control erosion.

To be acceptable to farmers, erosion control measures must be effective, not

require too much additional labor or money, and maintain or increase yield or income.

Farmers in Thailand and Vietnam generally selected vetiver grass as the most effective

way to reduce erosion, but its adoption on a large scale may still be limited because of

unavailability of planting material, high cost of transport and planting, and lack of direct

use of the grass except as mulch. For that reason, many farmers in Vietnam prefer

contour barriers of Tephrosia candida, which is less effective in controlling erosion, but

easier to establish and more useful as a green manure. In Indonesia vetiver grass was

not included in the demonstration plots until the second year; once included farmers seem

to appreciate its effectiveness in controlling erosion, but adoption will be slow because

of lack of planting material and its unsuitability as an animal feed.

Intercropping cassava with peanut is a new and very useful technology for

farmers in the three sites in Vietnam as well as in Baisha county of China. In some parts

of China, intercropping with peanut, however, is impossible due to serious damage

caused by rats. In Thailand, plowing with tractor is usually done up-and-down the slope

and/or parallel to roads or field borders. Contour hedgerows of any species will interfere

with this practice, while curved hedgerows will also interfere with the planting of cassava

in straight lines using tight ropes as a guide. These practical problems are likely to limit

adoption of contour hedgerows. In fields with uniform and unidirectional slopes, the

planting of straight hedgerows or barrier strips across the slope, however, may be

acceptable. Intercropping with sweetcorn or pumpkin is rather new in Thailand, but the

susceptibility of these crops to drought or excessive moisture will limit their adoption.

In Indonesia cassava farmers already use many soil conserving practices, such

as terracing (especially in Java), agro-forestry, intercropping, and manure or fertilizer

513

application. Fields tend to be very small and often bordered by hedgerows of grass

(mainly elephant grass) or tree legumes (mainly Gliricidia sepium, Leucaena

leucocephala, or Calliandra). Some of these essentially function as contour barriers.

Farmers have shown little spontaneous interest in the project because of lack of attractive

new options, alternatives that are either more effective or more beneficial than what

farmers are already doing. The inclusion of vetiver grass in the demonstration plots in

Malang showed farmers a highly effective erosion control option, but this technology may

still find little adoption because of other limitations, as discussed above. The challenge

for Indonesian team members is to find truly superior alternatives to what farmers are

already doing now.

5. Institutionalization of a Participatory Approach in Research and Extension

Traditionally, governments in Asia, whether communist or democratic, have all

used a top-down approach in the research-extension continuum, i.e. researchers do

research, usually at experiment stations, and based on their results make

recommendations, which are then extended by extensionists to farmers. Farmers have

no input in setting research priorities and they either accept or reject the

recommendations of the extensionists. This system works reasonably well for those

technologies, like new varieties, that are readily accepted anyway because they increase

farmers benefits at little additional cost. Fertilizer practices are also easily accepted if

the benefits clearly outway the costs, and if farmers have the resources to buy the

fertilizers. However, for knowledge-intensive technologies, like erosion control

practices, which are often highly site-specific, the practices recommended in this top-

down approach are either not the best for the specific location or require too much

additional inputs in comparison to the perceived benefits. The participatory approach

used in this FPR project assures that the technologies are better tailored to farmers' needs

and to the specific conditions in the pilot sites. Moreover, as farmers are directly

involved in the testing and selection of the best practices they are more likely to develop

practices that are acceptable and adoptable, thus eventually leading to greater use of

sustainable production practices. However, to reach a much wider audience of farmers

beyond the pilot sites, either involving them directly in FPR, or at least convincing them

of the usefulness of those practices developed by fellow farmers in the same area, it is

necessary to involve many more researchers and extensionists in the process. This can

only be done if local administrators and policy makers are convinced that FPR is an

efficient and effective methodology for the development and transfer of site-specific

technologies, and are willing to adopt a more participatory and bottom-up approach

within their own institutions. This FPR project on enhancing the sustainability of cassava

production in Asia, is a rather insignificant endeavor in the whole realm of things, but

can become significant if we can convince policy makers of the effectiveness of the

methodologies used, and contribute to the institutionalization of a more participatory

514

approach in national research and extension organizations.

Moreover, as evidenced in cassava processing projects in Colombia and Ecuador

(Ospina et al., 1996), collaborating farmers themselves, once trained and experienced in

FPR in their own sites, are excellent transfer specialists to other farmers, especially when

technologies are more complicated, as is the case for processing and erosion control. As

is already pointed out, it will take significant human resources to transfer the FPR

approach as well as the technologies developed to other villages and regions. Hence, the

collaboration of farmers as alternative transfer agents (farmer-to-farmer extension) could

be a viable option for the future.

REFERENCES

Ashby, J. A. 1997. What do we mean by participatory research in agriculture? In: New Frontiers

in Participatory Research and Gender Analysis. Proc. Int. Seminar on Participatory Research

and Gender Analysis for Technology Development, Cali, Colombia. Sept 9-14, 1996. pp.15

-22.

Nguyen The Dang, Tran Ngoc Ngoan, Le Sy Loi, Dinh Ngoc Lan and Thai Phien. 1998. Farmer

participatory research in cassava soil management and varietal dissemination in Vietnam. In:

R.H. Howeler (Ed.). Cassava Breeding, Agronomy and Farmer Participatory Research in Asia.

Proc. 5th Regional Workshop, held in Danzhou, Hainan, China. Nov 3-8, 1996.

Ospina, B., S. Poats and G. Henry. 1996. Integrated cassava research and development projects

in Colombia, Ecuador and Brazil; an overview of CIAT's experiences. In: D. Dufour, G.M.

O'Brien and R. Best (Eds.). Cassava Flour and Starch: Progress in Research and Development.

Proc. Workshop held in Cali, Colombia. Jan 1994. CIRAD/CIAT, Cali, Colombia. pp.333-

357.

Utomo, W.H., Suyamto, H. Santoso and A. Sinaga. 1998. Farmer participatory research in soil

management in Indonesia. In: R.H. Howeler (Ed.). Cassava Breeding, Agronomy and Farmer

China. Nov 3-8, 1996.

Vongkasem, V., K. Klakhaeng, S. Hemvijit, A. Tongglum, S. Katong and D. Suparhan. 1998.

Farmer participatory research in soil management and varietal selection in Thailand.

In: R.H. Howeler (Ed.). Cassava Breeding, Agronomy and Farmer Participatory Research in

Asia. Proc. 5th Regional Workshop, held in Danzhou, Hainan, China. Nov 3-8, 1996.

Zhang Weite, Lin Xiong, Li Kaimian and Huang Jie. 1998. Farmer participatory research in

cassava soil management and varietal dissemination in China. In: R.H. Howeler (Ed.). Cassava

Breeding, Agronomy and Farmer Participatory Research in Asia. Proc. 5th Regional

Workshop, held in Danzhou, Hainan, China. Nov 3-8, 1996.

515

CASSAVA BIOTECHNOLOGY NETWORK

Ann Marie Thro1

INTRODUCTION

The objective of this session is to provide all participants in the Asian Cassava

Research Network, regardless of specialization, with a common background for

evaluating the usefulness of biotechnology tools for Asian cassava research and

development.

Specific Objectives

-Briefly describe biotechnology tools available for cassava

-Review types of research objectives for which each biotechnology tool is appropriate

-Consider other factors important for using each tool effectively (time to output, relative

costs to be measured, etc)

Target Outcomes for Participants and CBN

-A common understanding of biotechnology tools and their functions

-A shared basis for evaluating whether or not biotechnology tools offer an advantage for

developing technical solutions to problems encountered in Asia for cassava

-Based on discussions and information during the Cassava Regional Workshop to obtain

a information assessment by Workshop participants of the following:

* Does biotechnology have any advantages to offer for cassava in Asia?

* How? What? Where?

* Is biotechnology being used effectively in those situations? What are the

elements of practical success?

* Where biotechnology could offer advantages but is not being used, what is

available and what is missing for effective action? Institutional linkages,

information, human resources, financial resources, research policies.. etc?

BIOTECHNOLOGY TOOLS FOR CASSAVA

I. Micropropagation (cell and tissue culture)

Genetic Biotechnologies ("gene technologies"):

II. Genetic engineering, or genetic transformation

III. Molecular markers

Microbial Biotechnology:

IV. Fermentation biotechnology

Cassava Biotechnology Network (CBN), CIAT, Apartado Aereo 67-13, Cali, Colombia.

516

Each Biotechnology Tool Does Something Different

-Molecular markers are a form of information technology; used to enhance breeders'

ability to assess and select genetic diversity.

-Genetic engineering is a way to extract and insert genes; used to enhance breeders'

access to genetic variations or to create new variation.

-Tissue culture is a method of vegetative propagation (cleaner, faster,...)

-Fermentation biotechnology is a way of changing a substrate; used to give cassava

greater value and/or new properties.

The nature of the technology determines how it is useful.

I. Micropropagation (Cell and Tissue Culture)

Used in at least 20 countries for conservation and sharing of cassava genetic

diversity Considered "conventional" for cassava by some. Widely used for cassava

because:

-Cassava varieties must be propagated by cuttings, which can transmit pests and diseases.

-Production of disease-free cuttings in tissue culture permits:

1 . Conservation of cassava genetic diversity without long-term build-up of pests and

diseases which may occur in field collections.

This requires a long-term funding commitment, which is often more problematic than

the technology itself.

Cryopreservation (freezing): Lower cost, long-term. Has been experimentally

successful, but requires pilot testing to assess genetic stability and operating costs.

2. Improved international access to cassava genetic diversity via clean propagules to

meet quarantine regulations.

3. Similarly, international sharing of experimental varieties, so breeding programs can

use varieties developed in similar environments.

This can be managed as shorter-term commitments. Tissue culture facilities can be

shared with other crops.

4. Renovation of infested important cultivars

Thermotherapy: virus/pest elimination.

Effective for yield increases over several years if rate of re-infection is slow.

If rate of re-infection is high (rapid), resistant cultivars are required.

Careful agronomic management is necesary: Loss of associated beneficial

microorganisms, or unusual infection of succulent plantlets just out of tissue culture,

can lead to disappointing yield "crashes".

5. Faster multiplication of desired cassava varieties ("in-vitro rapid micropropagation")

Potential (biologically-achievable) rates per year:

Field multiplication: tens of plants from one plant

517

Single-or two-node cutting multiplication: thousands from one

Tissue culture: millions from one

Some of the factors affecting success:

-Selection of plant materials for tissue culture multiplication. Clones must be well-tested

with target users.

-Health status of source material.

-Post-flask management (hardening, "weaning")

Requires investment of experienced supervision, labor, water, materials (screening...).

Succulent tissue more susceptible than usual to pests and diseases.

-Integration with existing program of field multiplication and distribution

Links with agricultural extension, NGOs, private sector.

Distribution logistics.

Pilot projects

-Information on costs and benefits

In emergencies when cassava varieties in a region must be changed or restored rapidly

due to abrupt social, economic, or biological events.

For normal progress in more stable situations

Facilities can be shared with other crops

-Requires management skills

For delivering plantlets on time

For efficient use of facilities

"Low tech biotech"

-A need to develop lower-cost methods for tissue culture

In-vitro culture protocols

Post-flask management

Plantlet distribution

Energy-efficient, use more local materials

General principals, site-specific aspects

Micro-propagation also permits regeneration of plants from single cells, an essential step

in genetic engineering.

II. Genetic Transformation ("Transgenesis")

"Transfer of a piece of DNA into a plant cell, followed by stable integration

in the genome" .

518

Used for traits that can be altered by a single-gene, or single-gene steps in

multigenic pathways.

Increase genetic diversity by inserting new genes into otherwise superior

varieties, or,

Alter the level of expression of existing genes above or below naturally-occurring

levels.

Promoters to enhance enzyme activity.

Anti-sense forms of existing genes, to inhibit gene action.

Examples of types of genes used in genetic transformation:

Resistances to viruses and other disease organisms.

Enzymes to transform the cassava root into a "biofactory" for biodegradable

plastics-polymers or other totally new products.

Genetic engineering can be used to create specific mutations, useful for studying

complex physiological traits, e.g. could permit the first definitive studies of the ecology

and biochemistry of cyanogens in cassava, to permit more effective and better-targeted

genetic manipulation of this trait (whether by plant breeding or genetic engineering).

Biological requirements

1. Efficient systems(s) for plantlet regeneration from single cells.

2. Efficient system (s) for transformation.

3. Efficient system for selection of transformed from non-transformed cells

immediately after transformation.

4. Transformation, selection, and regeration systems must be compatible, i.e.

-Transformable cells must be regerable.

-Transformation and selection systems must not have too negative an effect

on regeneration.

5. Isolated (cloned) genes available:

Marker genes.

Genes for desired agronomic or quality characteristics.

Types of transformation systems either through vectors or by direct gene transfer

/. Vectors: usually Agrobacterium

Agrobacteria can transfer a piece of DNA from a region of an extra-chromosomal part

of their DNA (the tumor-inducing Ti plasmid) to a plant cell. The Ti plasmid contains

important regions necessary for successful transfer of DNA to the plant.

Transfer DNA (T-DNA), the region actually transferred to the plant cell. The

gene to be transferred is inserted into the T-DNA region.

519

Virulence or Vir-region, containing genes which determine whether and how

efficiently the T-DNA is transferred to the plant cell.

In nature: Several other genes involved in formation and breakdown of opines

(sugar amino acids) and so-called Oflc-genes

Agrobacterium "breeding" has created strains with additional and more effective Vir

genes, capable of transforming additional species, more effciently.

Integration of DNA in the genome of the plant by the bacterium occurs at random,

although there seems to be preference for certain transcriptionally-active regions.

Advantages of Agrobacterium methods

More suitable for simple laboratory conditions, require only the equipment and

supplies of a normal microbiology and tissue culture laboratory.

Possibly fewer stuctural changes or amplifications in the genes inserted, low

number of copies inserted compared to direct gene transfer methods.

Tend to give more normal gene expression and inheritance

2. Direct gene transfer

Examples: - Micro-injection of individual cells with DNA.

- Micro-projectile bombardment (biolistics). Gold "bullets" coated with

DNA are transferred into plant tissue (intact cells) by high velocity

force using a "gene gun".

- Electroporation of DNA into protoplasts.

Frequencies of success using direct gene transfer range from 0.1% to 10%

depending on the plant species and the procedure used. Generally less efficient than

Agrobacterium, for which success ranges from 1% to 90%.

More costly (specialized equipment and maintenance).

However: The only alternative for many monocot species not susceptible to

Agrobacterium.

Less genotype-dependent than Agrobacterium methods.

Factors influencing expression of transgenic traits

So-called "position effects", the actual position on the chromosome (hard to influence)

Environmental factors (GxE)

Structure of gene to be integrated (codon composition, borders, regulatory elements such

as promoters, enhancers, introns, etc..) (can be manipulated)

520

Type of gene to be integrated:

Genomic sequence from same species:

60-90% of transformants have desired expression

Anti-sense sequence (e.g., "turning off' a gene): 0-50%

Heterologous sequence (gene from another species): 1-40%

When to select and evaluate products of genetic transformation

-Before or during regeneration of transformed cells

-During tissue-culture growth of transformed plantlets

-Based on greenhouse growth and performance

-Based on field characteristics and performance

-Based on inheritance of traits by offspring (gene can remain present but become

silenced, or expression level can change)

Field selection and inheritance are the ultimate test; also most expensive; eliminate as

much material as possible in earlier stages

Genetic engineering of cassava:update

Cassava genetic engineering research began in 1987.

The only systems successful for regeneration of cassava cells are adversely effected by

transformation and selection.

Result: progress has been slow and difficult.

Breakthroughs in 1996; dramatic progress since last biennial report in 1994.

Regeneration of transgenic plants using microbombardment of embryogenic suspension

cell cultures (Agri. Univ. Wageningen, Netherlands; ILTAB/ORSTOM, USA/France)

Agrobacterium transformation of somatic embryo-derived cotyledons with subsequent

regeneration via organogenesis (ETH, Zurich).

Wild Agrobacterium strain to infect somatic embryo-derived cotyledons and regeneration

through somatic embryogenesis (CIAT).

New gene promoters

From cassava vein mosaic virus: potential to replace the commonly-used CaMV

35S promoter in cassava transformation (ILTAB); available on request to

researchers in cassava growing countries.

521

Possible root-specific promoter (Univ. Newcastle, UK).

Next steps

1 . Introduction of genes of agronomic interest

a. Genes available:

Resistance to viral diseases (CasCMV, ACMV)(Africa)

Starch concentration, quality (S.America, Asia)

Modification of cyanogen metabolism (Africa, S. America)

b. Genes not yet available for:

Reduced postharvest perishability of cassava (global)

Other...

c. Genetic transformation as a basic research tool (global)

Mechanisms of insect and disease resistance

Nutrient use efficiency

Drought tolerance

Photosynthesis

Cyanogenesis

2. Simplify and improve the new experimental protocols for cassava genetic engineering

(repeatability, efficiency).

3. Extend genetic tranformation protocols to a range of important cultivars

4. Continue to identify tissue-specific gene promoters

Outlook for the next few years:

Improved protocols ready for technology transfer to cassava-growing countries (3 to 5

years)

Transgenic cassava with genes of interest, ready for field trials (5 years?)

Therefore, planning phase should start now for:

-Transfer of improved protocols to additional laboratories

-Biosafety

-Design of evaluation of transgenic prototypes with applied researchers and

cassava users

III. Molecular Markers

Genetic variation is:

The basis of plant taxonomy, classification, germplasm evaluation

The basis of crop improvement.

What plant breeders do:

Detect and measure the genetic variation available and combine it into new

varieties by using cycles of crossing, selection, crossing again,... to combine and

522

recombine genes.

How plant breeders detect and measure genetic variation:

Inferred from the phenotype: measurements of morphology, performance,

analyzed via quantitative genetics ("organized ignorance"),

or, Direct from the genotype via molecular markers (also requires quantitative

analysis!).

Molecular marker types

Isozymes: limited amount of variation; inexpensive; recommended when

sufficiently informative.

DNA sequence markers

DNA sequence marker types: RFLPs, RAPDs, Microsatellites, AFLPs, etc.

....a rapidly-evolving technology..

Characteristics of different DNA marker types:

1. RFLPs (Restriction fragment length polymorphisms)

Uses "restriction" enzymes which cut DNA at specific bases sequences.

Resulting fragments separated on a gel by electrophoresis.

Genetic variation detected as differences in the size of fragments.

Advantage: Very reproducible (reliable) from lab to lab and species to species

Specific to particular sequences

Disadvantage: Expensive

Require radioactive labels (research to develop non-radioactive

methods)

2. RAPDs (Random amplified polymorphic DNA)

Uses polymerase chain reaction (PCR) which polymerizes nucleotides into

polynucleotide chains) and a single small primer (starter sequence), which

is likely to occur at random in a genome.

Advantage: Easy and quick.

Disadvantage: Not always reliable.

Not easy to target a specific area of the genome.

Can not distinguish heterozygotes from homozygous dominant

(less genetic information than RFLPs).

3. Microsatellites

Uses PCR with long (and therefore more specific) primers.

Identifies areas with long tandem (one-after-the-other) repeats of a short

DNA sequence.

Name refers to appearance of this type of DNA after centrifuging a

fragmented sample of total DNA: a microsatellite apart from the rest of the

DNA.

Advantage: Can target a specific area of the genome.

523

More variability than any other market type—can detect variation

among more closely related genotypes than can be distinguished

by other marker types.

Disadvantage: Expensive.

Requires DNA sequence analysis to create the primers.

4. AFLPs (Amplified fragment length polymorphisms)

A combination of RFLP and PCR technology:

Cut DNA with restriction enzymes.

Attach short DNA "adapters" (known primers) to the ends of the fragments.

Amplify the fragments using the primers.

Advantage: Reproducible (reliable), easy.

Disadvantage: Can not easily target a specific area of the genome.

Usually does not distinguish heterozygote from homozygous

dominant.

Basically...differences between molecular marker types are related to how much they cost

vs. amount of information and reliability

Uses of molecular markers

1. Germplasm screening

Measure differences and assay relationships. Easiest with AFLPs or RAPDs.

2. Construction of genetic maps

General-purpose tools for gene tagging, quantitative trait analysis, and map-based

cloning.

3. Tagging of genes for indirect selection

- To find molecular markers closely linked to the gene of interest, especially for

difficult- or expensive-to-measure traits (e.g. insect resistance, traits with high

GxE), or traits that can be measured only late in the life cycle (e.g. post-harvest

perishability).

- Then pre-select based on the marker (and select against undesirable linked

genes), confirm field phenotype with smaller number.

- Increases efficiency of field testing.

- Less expensive? depends on the situation and the trait!

4. Quantitative trait analysis

- Follow segregation of a large number of RFLP markers in a single cross.

- Correlate presence of a certain marker (e.g., chromosome segment) with the

quantitative trait.

- Assemble genotypes containing multiple favorable chromosome segments

(markers) for the quantitative trait (QTLs).

5. Map-based cloning of genes

524

A method of isolating genes for genetic engineering, when there is little

information about the gene.

6. Analysis of introgression

Increased speed of gene transfer via backcrossing.

Select against unfavorable linked genes from donor parent.

IV. Traditional and Contemporary Fermentation Biotechnology

Used for centuries to preserve and detoxify cassava

Improved starter cultures can enhance safety, nutritional value, and consumer

appeal of traditional cassava foods.

Contemporary fermentation technology: a growth industry that uses cassava

substrate to produce a range of products, from animal feeds to industrial enzymes

and pharmaceuticals.

Need for consumer-oriented market research and product development activity.

Microbial biotechnology for waste management

Treatment of cassava processing waste water and solids

Environmental protection, clean water conservation

Detoxification

Reduction of biological oxygen demand

Value added?

525

Workshop Participants

China

Zheng Xueqin, Wang Shengxian, Lin Xiong, Zhang Weite, Li Kaimian,

Huang Jie, Jiang Changshun, Tang Yuedong and Wu Hao

Chinese Academy of Tropical and Agricultural Sciences (CATAS)

Baodao Xincun, Danzhou, Hainan, 571737, P.R. China

Fax (86-890) 330-0776 or 330-0157

Du Daolin

Dept. Biology, Hainan Teachers College

Haikou, Hainan 571158, P.R. China

Zhuang Zhong Tang and Liu Jin Ping

Honghe Animal Husbandry Station of Yunnan

Livestock Academy, Science and Technology Service Dept.

West suburb, Mengzhe county

Yunnan, 661100, P.R. China

Tiang Yinong and Li Jun

Guangxi Subtropical Crops Research Institute (GSCRI)

22 Yongwu road, Nanning

Guangxi, P.R. China

Fax (86-771) 280-6902

Yang Mu Cheng

Guangxi Science and Technology Information Institute

Nanning, Guangxi, P.R. China

Liu Yin Fei

Liuzhou Science and Technology Information Institute

Liuzhou, Guangxi, P.R. China

Fang Bai Ping and Fu Guo Hui

Upland Crops Research Institute (UCRI) of Guangdong Acad. Agric. Sciences

Wushan, Guangzhou, Guangdong, 510640, P.R. China

Fax (86-20) 875-03358

He Ya Wen, Ma Guo Hua and Zhu Yi

South China Institute of Botany

Guangzhou, Guangdong, P.R. China

526

He Lui Zhi

Science and Technology Department

Haikou, Hainan, P.R. China

Ou Ji Chang

Planning Department

Haikou, Hainan, P.R. China

Liang Feng Fei

Nankun Starch Factory

Nankun, Tunchang County, Hainan, P.R. China

Liu Kuan Tang

Long-chang Agriculture Development Company

Chang-Jiang County, Hainan, P.R. China

Colombia

Sam Fujisaka, Guy Henry and Ann Marie Thro

Centra Internacional de Agricultura Tropical (CIAT)

Apartado Aereo 67-13, Cali, Colombia

Fax (57-23) 445-0273

India

G.T. Kurup, S.G. Nair, C.R. Mohan Kumar, V.P. Potty and S. Ramanathan

Central Tuber Crops Research Institute (CTCRI)

Thiruvananthapuram, Kerala, 695017, India

Fax (91-471) 550-063

S. Thamburaj

Horticultural College and Research Institute

Tamil Nadu Agricultural University

Coimbatore, Tamil Nadu, 6410003, India

Fax (91-422) 431-672

Indonesia

Yogi Sogito, Soemarjo Poespodarsono, Wani Hadi Utomo and Heru Santoso

Brawijaya University

Malang, East Java, Indonesia

Fax (62-341) 364-487

527

Suyamto H., Director

Research Inst, for Legumes and Tuber Crops (RILET)

P.O. Box 66, Malang, East Java, Indonesia

Fax (62-341) 801-4%

J. Wargiono

Bogor Biotechnology Institute

Jl. Cimanggue 3A

Bogor, West Java, Indonesia

Fax (62-251) 312-755

Usman Kartawijaya and Palupi Puspitorini

P.T. Great Giant Pineapple Coy

Jl. KH Moch, Salem 28, Way Lunik

Panjang-Bandar Lampung, Lampung, Indonesia

Fax (62-721) 31972 or (62-725) 41742

Malaysia

Tan Swee Lian

Malaysian Agric. Research and Developm. Institute (MARDI)

G.P.O. Box 12301, 50774 Kuala Lumpur, Malaysia

Fax (60-3) 948-3664 or 948-2961

Philippines

Fernando Evangelio, Editha Gundaya and Reynaldo Bergantin

Philippines Root Crops Research and Training Center (PRCRTC),

8 Lourdes Street

Pasay City 3129, Metro Manila, Philippines

Fax (63-2) 588-692

Thailand

Chareinsuk Rojanaridpiched and Vicharn Vichukit

Faculty of Agriculture, Kasetsart University

Chatuchak, Bangkok 10900, Thailand

Fax (66-2) 579-8536

Cham Tirapom and Preecha Suriyapan

Department of Agriculture


Fax (66-2) 561-3486, 940-5418

528

Watana Watanonta, Jarungsit Limsila, Anuchit Tongglum,

Danai Suparhan and Somphong Katong

Rayong Field Crops Research Center

Huay Pong, Rayong, Thailand

Fax (66-38) 681-515

Wilawan Vongkasem, Kaival Klakhaeng and Somnuek Hemvijit

Rice and Field Crops Promotion Div.

Dept. of Agricultural Extension (DOAE)

Charuchak, Bangkok 10900, Thailand

Fax (66-2) 579-2622

Piyawuti Poolsanguan

Sri Racha Research Station of KU

Sri Racha, Chonburi, Thailand

Vanna Changesrisook and Somporn Phongvutiprapan

Thai Tapioca Development Institute (TTDI)

1 168/32 Lumpini Tower, 16th floor

Rama IV Road, Bangkok 10120, Thailand

Fax (66-2) 285-6647

Kazuo Kawano and Reinhardt Howeler

CIAT Regional Office, Dept. of Agriculture


Fax (66-2) 940-5541

Vietnam

Truong Van Ho, Trinh Thi Phuong Loan and Hoang Van Tat

Root Crops Research Center

National Inst. Agric. Sciences (INSA)

Van Dien, Thanh Tri, Hanoi, Vietnam

Fax (84-4) 253-525 or 613-937

Thai Phien

Institute for Soils and Fertilizers

Chem, Tu Liem, Hanoi, Vietnam

Fax (84-4) 834-3924

529

Tran Ngoc Ngoan, Nguyen The Dang, Le Sy Loi and Dinh Ngoc Lan

Agro-forestry College of Thai Nguyen University

Thai Nguyen, Bac Thai, Vietnam

Fax (84-28) 852-921

Pham Van Bien, Hoang Kim and Nguyen Huu Hy

Institute of Agric. Science of South Vietnam (IAS)

121 Nguyen Binh Khiem Street

Ho Chi Minn city, Vietnam

Fax (84-8) 8297-650 and (84-61) 868-120

Pol Deturck

Vietnam-Belgium Project on Sustainable Agric. Developm. in the

Uplands of South Vietnam

Institute of Agric. Science of South Vietnam (IAS)

121 Nguyen Binh Khiem Street

Ho Chi Minn city, Vietnam

Fax (84-8) 8297-650

530

APPENDIX

Results of Soil Analyses in Asia 1994-1997

R.H. Howeler1

The following tables present the analysis results of soil samples taken in various

countries in Asia, mainly in soil fertility maintenance experiments and in FPR trials in

farmers fields. To facilitate interpretation of the results, Table 1 indicates the

approximate classification of soil chemical characteristic according to the nutritional

requirements of cassava.

Table 1. Approximate classification of soil chemical characteristics according to the

nutritional requirements of cassava.

Soil parameter" Very low Low Medium High Very high

pH <3.5 3.5-4.5 4.5-7 7-8 >8

Org. matter (%) <1.0 1.0-2.0 2.0-4.0 >4.0

Al-saturation (%) <75 75 -85 >85

Salinity (mmhos/cm) <0.5 0.5- 1.0 >1.0

Na-saturation (%) <2 2- 10 >10

P (Mg/g) <2 2-4 4- 15 >15

K (me/IOOg) <0.10 0.10-0.15 0.15 -0.25 >0.25

Ca (me/IOOg) <0.25 0.25- 1.0 1.0-5.0 >5.0

Mg (me/IOOg) <0.2 0.2-0.4 0.4- 1.0 >1.0

S (Mg/g) <20 20-40 40-70 >70

B (/ig/g) <0.2 0.2-0.5 0.5 - 1.0 1 -2 >2

Cu Ozg/g) <0.1 0.1 -0.3 0.3 - 1.0 1 -5 >5

Mn 0-ig/g) <5 5 - 10 10- 100 100 - 250 >250

Fe (/ig/g) <1 1 - 10 10- 100 > 100

Zn (/ig/g) <0.5 0.5- 1.0 1.0-5.0 5-50 >50

11 pH in H2O; OM by method of Walkley and Black;

Al saturation = 100xAl/(Al + Ca + Mg + K) in me/IOOg;

P in Bray II; K, Ca, Mg and Na in IN NH4-acetate; S in Ca-phosphate;

B in hot water; and Cu, Mn, Fe and Zn in 0.05 N HC1 +0.025 N H2SO4

CIAT Cassava Asian Regional Program, Dept. Agric., Chatuchak, Bangkok, Thailand.

531

Table 2. Soil samples taken in China.

Sample no. Sample location and description Date Lab Series

Hainan -1 Quongzhong county, Changzhang- area cleared for cassava

-2 Baisha county, Kongba village - black soil

-3 Baisha county, Kongba village - black soil in fertilizer trial

-4 Kongba village - Mr. Pu Yong Chuan, FPR fert. trial check

-5 Kongba village - Mr. Tan Jing Zhou, FPR fert. trial check

-6 Kongba village - Mr. Tan Jia Chai, FPR fert. trial check

-7 Kongba village - Mr. Tan Yin Zhui FPR fert. trial check

-8 Kongba village - Mr. Tan Ya Zhui, FPR fert. trial check

-9 Kongba village - Mr. Zhou Shao Xiong, FPR fert. trial check

-10 Kongba village - Mr. Tan Ming Lei, poor eroded soil

-11 Kongba village - Mr. Tan Yen Chai, FPR erosion trial

-12 Kongba village - Mr. Zhou Ya Nin, FPR fert. trial check

-13 Kongba village - Mr. Tan Ya Tian, FPR fert. trial check

-14 Kongba village - Mr. Ma Guo Rong, FPR fert. trial check

-15 Kongba village - Mr. Fu Yong Chuan, FPR fert. trial check

-16 CATAS - NPK trial, 1995, 4th year, NoP^

-17 CATAS - NPK trial, 1995, 4th year, N3P3K3

-18 CATAS - NPK trial, 1996, 5th year, NoPoKo

-19 CATAS - NPK trial, 1996, 5th year, N,P3K3

Guangxi -1 Nanning, NPK trial, 1994, 6th year, N^oK,,

-2 Nanning, NPK trial, 1994, 6th year, N3P3K3

-4 Nanning, NPK trial, 1995, 7th year, N^oK,


-6 Nanning, NPK trial, 1996, 8th year, NqPoKo


Guangdong -1 Huayji, on-farm NPK trial, before planting

-2 Gaozhou Agric. College, NPK trial, before planting

-3 Yunnan, on-farm NPK trial, before planting

Nov 95 S498

Nov 95 S498

Nov 95 S498

Jan 95 S498

Jan 95 S498

Jan 95 S498

Jan 95 S498

Jan 95 S498

Jan 95 S498

Jan 97 S782

Jan 97 S782

Jan 97 S782

Jan 97 S782

Jan 97 S782

Jan 97 S782

Mar 95 S498

Mar 95 S498

Mar 95 S782

Mar 96 S782

Feb 94 S891

Feb 94 S891

Mar 95 S498

Mar 95 S498

Mar 96 S782

Mar 96 S782

Mar 96 S782

Mar 96 S782

Mar 96 S782

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Table 4. Soil samples taken in Indonesia.

Sample no. Sample location and description Date Lab Series

E-Java -1 Malang, Jatikerto

-2 Malang, Jatikerto

-3 Blitar, Ringinrejo





-8 Malang, Dampit,

-9 Malang, Dampit,

-10 Malang, Dampit,

-1 1 Malang, Dampit,

NPK trial, 1995, 8th year, NoP^

NPK trial, 1995, 8th year, N3P3K3

Demonstration plots, black soil + lime

, Mr. Ponirin - erosion trial, red clay

Mr. Hardi - variety trial, black soil

, Mr. Katimin - erosion trial

, white purple clay in road cut

demonstration plots - T2, severe K def.

demonstration plots - T,2, no K deficiency

Ir. Noviar erosion trial, severe K def.

K trial before planting

Oct 95 S498

Oct 95 S498

Febr 96 S498

Febr 96 S498

Febr 96 S498

July 96 S782

July 96 S782

July 96 S782

July 96 S782

July 96 S782

Sept 96 S782

Yogyakarta -1 Playen, farmer's field - Fert x soybean trial Febr 96 S498

Lampung -1 Umas Jaya, NPK trial, 1996, 9th year, Av. N^Ko

-2 Umas Jaya, NPK trial, 1996, 9th year, Av. N3P3K3

-3 Tamanbogo, erosion trial, 1994/95, 5th year, T,

-4 Tamanbogo, NPK trial, 1994/95, 4th year, N0PoKo

-5 Tamanbogo, NPK trial, 1994/95, 4th year, N3P3K3

-6 Tamanbogo, NPK trial, 1995/96, 5th year, N0PoKo

-7 Tamanbogo, NPK trial, 1995/96, 5th year, N3P3K3

Febr 96 S498

Febr 96 S498

Dec 94 S782

Dec 94 S782

Dec 94 S782

Sept 95 S782

Sept 95 S782

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Table 8. Soil samples taken in Thailand.

Sample no. Sample location and description Date Lab series

N.Ratchasima

Sra Kaew

-1

-2

-3

-4

-5

-6

-7

-8

-9

-10

-11

-12

-13

-14

-15

-1

-2

-3

-4

-5

-6

Soeng Saeng, Mr. Nonglak - FPR erosion trial

Soeng Saeng, Mr. Saway - FPR erosion trial

Soeng Saeng, Mrs. Kaew - FPR erosion trial

Soeng Saeng, Mrs. Thong - FPR erosion trial

Soeng Saeng, Mrs. Lamun - FPR erosion trial

Soeng Saeng, Mrs. Nuukaan - FPR erosion trial

Soeng Saeng, Mrs. Kong - FPR erosion trial

Soeng Saeng, Mrs. Wongduean - FPR variety trial

Soeng Saeng, Mr. Thongchan - FPR fert. trial check.

Banmai Samrong NPK trial, 21st year, 0-0-0

Banmai Samrong NPK trial, tops incorp + 8-8-8

Huay Bong, Daan Khun Thot - TTDI - demonstr. plots

Huay Bong, Daan Khun Thot - TTDI-long-term trial 1-1

Huay Bong, Daan Khun Thot - TTDI-long-term trial II- 1

Highway Paakchong-Huay Bong-Field with Fe/Zn def.

Wang Nam Yen,

Wang Nam Yen,

Wang Nam Yen,

Wang Nam Yen,

Wang Nam Yen,

Mr

Mr

Mr

Mr

Mr

Wang Nam Yen, Mr

Sawong - FPR erosion trial

Bunlue - FPR erosion trial

Udom - FPR erosion trial

Prichaa - FPR erosion trial

Lek - FPR variety trial

Bunlue - FPR erosion trial

July 95 S-498

July 95 S-498

July 95 S-498

July 95 S-498

July 95 S-498

July 95 S-498

July 95 S-498

July 95 S-498

Mar 96 S-498

July 95 S-498

July 95 S-498

July 95 S-498

July 96 S-782

July 96 S-782

July 96 S-782

July 95 S-498

July 95 S-498

July 95 S-498

July 95 S-498

July 95 S-498

Dec 95 S-498

Prachin Buri -1 Khaw Hin Sorn-grass barrier trial July 96 S-782

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Table 10. Soil samples taken in Vietnam.

Sample no. Sample location and description Date Lab series

Dong Nai -1 Hung Loc Center, Soil Improvement trial, 1994/95, 3d year, T,

-2 Hung Loc Center, Soil Improvement trial, 1995/96, 4th year, T,

-3 Hung Loc Center, Soil Improvement trial, 1996/97, 5th year, T,

-4 Hung Loc Center, Soil Improvement trial, 1996/97, 5th year, T8

-5 Hung Loc Center, NPK trial, 1994/95, 5th tear, N0PoK0

-6 Hung Loc Center, NPK trial, 1995/96, 6th year, N^K,,

-7 Hung Loc Center, NPK trial, 1996/97, 7th year, N^Kc

-8 Hung Loc Center, NPK trial, 1996/97, 7th year, N3P3Kj

-9 Thong Nhat, Traco village, NPK trial, 1995/96, N0PoKj

-10 Thong Nhat, Traco village, new NPK trial before planting

Thai Ninh -1 Farmers' field

Bac Thai -1 Agro-forestry College, NPK trial, 1996, 7th year, N0PoK0

-2 Agro-forestry College, NPK trial, 1996, 7th year, N3PjK3

-3 Agro-forestry College, erosion trial, 1996, T,

-4 Agro-forestry College, Mg trial, 1996, before 1st year planting

-5 Agro-forestry College, FPR demonstration plots, 1996

-6 Pho Yen, Tien Phong, Mr. Nguyen Van Dung, erosion trial

-7 Pho Yen, Tien Phong, Mr. Ngo Dinh Thuong, variety trial, Mg def.

-8 Pho Yen, Dac Son, Mr. Nguyen Van Du, K and Mg deficiency

Vinh Phu -1 Thanh Hoa, Kieu Tung, FPR fertilizer trial check plot

Hoa Binh -1 Luong Son, Dong Rang, farmer's field, FPR variety trial

-2 Luong Son, Dong Rang, erosion trial, T, (no fertilizers)

Apr 94 S-498

May 95 S-498

May 96 S-782

May 96 S-782

Apr 94 S-498

Apr 95 S-498

May 96 S-782

May 96 S-782

June 95 S-498

May 96 S-782

June 95 S-498

Jan 96 S-498

Jan 96 S-498

Jan 96 S-498

Jan 96 S-498

Jan 96 S-498

Oct 95 S-498

Oct 95 S-498

July 96 S-782

Oct 95 S-498

Apr 96 S-498

July 96 S-782

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